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A compact single-layer, polarization-insensitive, and angularly stable frequency selective surface (FSS) based multi-stop band filter is reported for shielding three useful frequency bands covering 1.82–2.86 GHz Industrial, scientific, and medical (ISM), 3.52–4.06 GHz Worldwide Interoperability for Microwave Access (WiMAX), and 7.42–8.72 GHz (satellite downlink), centered at 2.4 GHz, 3.6 GHz, and 8.1 GHz, respectively. The proposed unit cell (15 mm × 15 mm) contains four equal-sized square-headed dumbbell (SHD) shaped resonators surrounded by two square ring resonators. The outer and inner square rings offer the first and second stop bands, while the SHD resonators provide the third stop band. A highly polarization-insensitive response is realized owing to the four-fold symmetry in the proposed structure. The unique arrangements of the SHD resonators help to realize higher angular stability under transverse electric (TE), transverse magnetic (TM), and diagonally polarized incident electromagnetic (EM) waves for incidence angles up to 80°, 80°, and 70°, respectively. A detailed analysis in terms of equivalent circuit and parametric variation is carried out to illustrate the higher to lower frequency band ratio. A prototype is fabricated and tested through a proper measurement setup to validate its performance, and it shows good agreement with the simulated results. The proposed FSS unit cell offers better angular stability under diagonally polarised incident waves, attenuation level, minimum higher to lower frequency band ratio, good fractional bandwidth, and compactness. So the designed multi-stopband FSS can be considered a potential candidate for shielding EM radiation across the useful bands

A compact single-layer, polarization-insensitive, and angularly stable frequency selective surface (FSS) based multi-stop band filter is reported for shielding three useful frequency bands covering 1.82–2.86 GHz Industrial, scientific, and medical (ISM), 3.52–4.06 GHz Worldwide Interoperability for Microwave Access (WiMAX), and 7.42–8.72 GHz (satellite downlink), centered at 2.4 GHz, 3.6 GHz, and 8.1 GHz, respectively. The proposed unit cell (15 mm × 15 mm) contains four equal-sized square-headed dumbbell (SHD) shaped resonators surrounded by two square ring resonators. The outer and inner square rings offer the first and second stop bands, while the SHD resonators provide the third stop band. A highly polarization-insensitive response is realized owing to the four-fold symmetry in the proposed structure. The unique arrangements of the SHD resonators help to realize higher angular stability under transverse electric (TE), transverse magnetic (TM), and diagonally polarized incident electromagnetic (EM) waves for incidence angles up to 80°, 80°, and 70°, respectively. A detailed analysis in terms of equivalent circuit and parametric variation is carried out to illustrate the higher to lower frequency band ratio. A prototype is fabricated and tested through a proper measurement setup to validate its performance, and it shows good agreement with the simulated results. The proposed FSS unit cell offers better angular stability under diagonally polarised incident waves, attenuation level, minimum higher to lower frequency band ratio, good fractional bandwidth, and compactness. So the designed multi-stopband FSS can be considered a potential candidate for shielding EM radiation across the useful bands

A compact single-layer, polarization-insensitive, and angularly stable frequency selective surface (FSS) based multi-stop band filter is reported for shielding three useful frequency bands covering 1.82–2.86 GHz Industrial, scientific, and medical (ISM), 3.52–4.06 GHz Worldwide Interoperability for Microwave Access (WiMAX), and 7.42–8.72 GHz (satellite downlink), centered at 2.4 GHz, 3.6 GHz, and 8.1 GHz, respectively. The proposed unit cell (15 mm × 15 mm) contains four equal-sized square-headed dumbbell (SHD) shaped resonators surrounded by two square ring resonators. The outer and inner square rings offer the first and second stop bands, while the SHD resonators provide the third stop band. A highly polarization-insensitive response is realized owing to the four-fold symmetry in the proposed structure. The unique arrangements of the SHD resonators help to realize higher angular stability under transverse electric (TE), transverse magnetic (TM), and diagonally polarized incident electromagnetic (EM) waves for incidence angles up to 80°, 80°, and 70°, respectively. A detailed analysis in terms of equivalent circuit and parametric variation is carried out to illustrate the higher to lower frequency band ratio. A prototype is fabricated and tested through a proper measurement setup to validate its performance, and it shows good agreement with the simulated results. The proposed FSS unit cell offers better angular stability under diagonally polarised incident waves, attenuation level, minimum higher to lower frequency band ratio, good fractional bandwidth, and compactness. So the designed multi-stopband FSS can be considered a potential candidate for shielding EM radiation across the useful bands

This contribution presents miniaturization techniques for folded circular substrate integrated waveguide (FCSIW) cavity filters. The cavities support dual-mode operation. Two of these cavities are combined to form a fourth-order filter. Two filter designs are implemented. The first one serves as a reference and exhibits good manufacturability. For the second one, the cavity is modified, which leads to 50% more compactness. The designs are experimentally verified with 10 GHz bandpass filters. Even though the achieved level of compactness requires higher technological effort, the measurements validate the miniaturization concept. The out-of-band rejection exceeds 40 dB between 11.2 and 30 GHz for the reference filter and between 11.3 and 33 GHz for the miniaturized one. The implemented components are compared with state-of-the-art filters.

In dieser Arbeit wird ein low-level-RF (LLRF)-System für die neuartige polarisierbare transversal ablenkende Struktur PolariX TDS entwickelt, installiert und an der FLASHForward-Beamline bei DESY in Betrieb genommen. Die PolariX TDS arbeitet im X-Band bei 12 GHz und erfordert ein LLRF-System, das Signale in diesem Frequenzband messen und verarbeiten kann. Mit einem Ansatz zur Wiederverwendung des bereits existierenden S-Band LLRF-Systems, das Signale bei 3 GHz verarbeiten kann, wird neue Hardware entwickelt, die HF-Signale zwischen 12 GHz und 3 GHz umwandelt. Die zugrundeliegenden Komponenten dieser Konvertierungshardware sind HF-Mischer, Filter, Verstärker und Frequenzvervielfacher. Verschiedene Kandidaten für all diese Komponenten werden charakterisiert und hinsichtlich ihrer elektrischen Eigenschaften verglichen. Da die endgültige Systemleistung stark vom Phasenrauschen abhängt, wird das Hauptaugenmerk der Charakterisierung auf dieses gelegt. Mit den ausgewählten Komponenten werden Leiterplatten entworfen, simuliert, produziert und in hermetisch dichte Gehäuse verpackt, bevor sie in 19"-Module eingebaut werden. Nach der Fertigstellung werden die Module ebenfalls im Labor charakterisiert. Als letzter Schritt wird der Prototyp der PolariX TDS zusammen mit dem entwickelten LLRF-System in der FLASHForward-Beamline installiert. Nach erfolgreicher Inbetriebnahme werden erste Messungen im laufenden Beschleuniger durchgeführt. Zur Analyse des Kurzzeitverhaltens werden mögliche Verfahren zur Eliminierung der Langzeiteffekte durchgeführt. Die Aktorkette, bestehend aus LLRF-System, Klystron und dessen Vorverstärker, wird vermessen und charakterisiert. Die Ergebnisse zeigen eine gewisse Diskrepanz zwischen erwarteten und gemessenen Werten und es wird eine Analyse möglicher Quellen des Problems durchgeführt. Mit Hilfe von strahlbasierten Messungen wird eine Beziehung zwischen der HF und dem Strahl hinsichtlich Phasen- und Amplitudenrauschen untersucht. Dies zeigt eine gute Le, In this thesis, a low-level RF (LLRF) system for the novel polarizable transverse deflecting structure PolariX TDS is developed, installed, and commissioned at the FLASHForward beamline at DESY. The PolariX TDS operates in the X-band at 12 GHz and requires an LLRF system capable of measuring and processing signals in this frequency band. Using an approach to reuse the existing S-band LLRF system that can process signals at 3 GHz, new hardware is being developed that converts RF signals between 12 GHz and 3 GHz. The underlying components of this conversion hardware are RF mixers, filters, amplifiers, and frequency multipliers. Various candidates for all these components are characterized and compared in terms of their electrical characteristics. Since the final system performance depends heavily on the phase noise, the main focus of the characterization will be on this. With the components selected, printed circuit boards are designed, simulated, produced and packaged in hermetically sealed housings before being mounted in 19" modules. After completion, the modules are also characterized in the laboratory. As a final step, the prototype of the PolariX TDS will be installed in the FLASHForward beamline together with the developed LLRF system. After successful commissioning, first measurements will be performed in the running accelerator. To analyze the short-term behaviour, possible procedures to eliminate the long-term effects will be discussed. The actuator chain, consisting of LLRF system, klystron and its preamplifier, is measured and characterized. The results show some discrepancy between expected and measured values and an analysis of possible sources of the problem is performed. Beam-based measurements are used to analyze the relation between the RF and the beam in terms of phase and amplitude noise. These measurements show good performance of the overall system in terms of short term phase stability in general. However, small deviations from the expected beha

Microwave absorbers present a wide range of applications in radar and telecommunications. To improve the microwave absorption characteristics of radar-absorbing structures (RASs), magnetic and dielectric materials are blended in different proportions because the impedance mismatch of dielectric materials, resulting from poor permeability, can be eliminated by a combination with magnetic loss fillers. Herein, E-glass/epoxy composites were prepared by blending multi-walled carbon nanotubes (MWCNTs) with Ni0.5Zn0.5Fe2O4 (NZF) nanopowder to enhance the composites’ microwave absorption. Nanocomposite laminates with different filler contents were fabricated by a simple and low-cost process of in situ polymerisation. The dielectric characteristics were estimated in the X-band, and possible loss mechanisms were studied. A two-layered RAS exhibited a reflection loss of −16 dB for a bandwidth of 2.2 GHz with a matching thickness of 3 mm. The resulting mechanical and thermal properties suggest that the proposed MWCNTs/NZF composite exhibiting good microwave absorption properties can be used in high-performance RASs., Microwave absorbers present a wide range of applications in radar and telecommunications. To improve the microwave absorption characteristics of radar-absorbing structures (RASs), magnetic and dielectric materials are blended in different proportions because the impedance mismatch of dielectric materials, resulting from poor permeability, can be eliminated by a combination with magnetic loss fillers. Herein, E-glass/epoxy composites were prepared by blending multi-walled carbon nanotubes (MWCNTs) with Ni0.5Zn0.5Fe2O4 (NZF) nanopowder to enhance the composites’ microwave absorption. Nanocomposite laminates with different filler contents were fabricated by a simple and low-cost process of in situ polymerisation. The dielectric characteristics were estimated in the X-band, and possible loss mechanisms were studied. A two-layered RAS exhibited a reflection loss of −16 dB for a bandwidth of 2.2 GHz with a matching thickness of 3 mm. The resulting mechanical and thermal properties suggest that the proposed MWCNTs/NZF composite exhibiting good microwave absorption properties can be used in high-performance RASs.

With the rise of 5G and the increasing number ofdevices, novel antenna designs are needed to meet the demandof the future. In this report, the authors present a design andexperimental verification of a 3D-printed Geodesic ModulatedReflective Luneburg lens antenna working at the X-Band, 8-12GHz. The lens profile is calculated from the refractive index of aflat system using transformation optics. Furthermore, the lens ismodulated to minimize the height and chamfers are implementedto reduce reflections. A sliding waveguide connected to a coaxialcable is used to excite the lens while the transmitted signal isradiated from a sinusoidal flare. A copper-lined PLA substrateconstitutes the 3D-printed lens. The authors achieved a S11 below-10 dB across the spectrum and a realized gain exceeding 10 dBacross the sweeping angles at 12 GHz, showcasing the usabilityas a directed antenna., Med det nya 5G nätverket och den ökandemängden enheter behövs nya antenner för att möta framtidensefterfrågan. I denna rapport presenterar författarna en designoch experimentell verifiering av en 3D-printad geodesisk moduleradreflekterande Luneburg linsantenn i X-bandet, 8-12 GHz.Linsprofilen beräknas från brytningsindexet för ett platt systemmed transformationsoptik. Dessutom är linsen modulerad föratt minimera höjden och kantavfasningar implementeras föratt minska reflektioner. En glidande vågledare ansluten till enkoaxialkabel används för att excitera linsen medan den sända signalenutstrålas från en vågledare med sinusformad avrundning.Ett kopparfodrat PLA-substrat utgör den 3D-printade linsen.Författarna uppnådde en S11 under -10 dB över spektrumet ochen realiserad förstärkning överstigande 10 dB över svepvinklarnavid 12 GHz, vilket visar linsens användbarhet som riktad antenn., Kandidatexjobb i elektroteknik 2021, KTH, Stockholm

Variation in canopy water content (CWC) that can be detected from microwave remote sensing of vegetation optical depth (VOD) has been proposed as an important measure of vegetation water stress. However, the contribution of leaf surface water (LWs ), arising from dew formation and rainfall interception, to CWC is largely unknown, particularly in tropical forests and other high-humidity ecosystems. We compared VOD data from the Advanced Microwave Scanning Radiometer for the Earth Observing System (AMSR-E) and CWC predicted by a plant hydrodynamics model at four tropical sites in Brazil spanning a rainfall gradient. We assessed how LWs influenced the relationship between VOD and CWC. The analysis indicates that while CWC is strongly correlated with VOD (R2  = 0.62 across all sites), LWs accounts for 61-76% of the diurnal variation in CWC despite being < 10% of CWC. Ignoring LWs weakens the near-linear relationship between CWC and VOD and reduces the consistency in diurnal variation. The contribution of LWs to CWC variation, however, decreases at longer, seasonal to inter-annual, time scales. Our results demonstrate that diurnal patterns of dew formation and rainfall interception can be an important driver of diurnal variation in CWC and VOD over tropical ecosystems and therefore should be accounted for when inferring plant diurnal water stress from VOD measurements.

A proven CubeSat form factor is leading to increasingly ambitious payloads and mission requirements, resulting in more data products and the need for higher space-to-ground transmission rates. This thesis contributes to the Naval Postgraduate School (NPS) CubeSat project and Mobile CubeSat Command and Control (MC3) initiative to increase network capacity through X-band downlinks. The Space Systems Academic Group at NPS is developing and fielding a 6U CubeSat with an X-band software-defined radio (SDR) payload, constructed using commercial-off-the-shelf hardware and operated via the MC3 ground station network. The objective of this thesis research was verification of end-to-end compatibility between the X-band SDR payload and MC3 ground station receivers. Research, testing, and analysis determined radio frequency signal parameters and communications standards that enable transmission of data from the X-band SDR payload to the AMERGINT satTRAC SDR and Kratos quantumRadio SDR receivers. Simulation (through MathWorks Simulink models) and interoperability testing were conducted. Research culminated in demonstration of a successful baseband link from payload SDR hardware to both ground station receivers, with a QPSK-modulated, PN11 data transmission. Further functional and environmental testing will ensure the X-band SDR payload can effectively communicate on-orbit with the MC3 network., Lieutenant, United States Navy, Approved for public release. Distribution is unlimited.

The objective of this research was to design, build, and test the next iteration of a low-cost, high-bandwidth X-band software-defined radio (SDR). The flight version of this iteration of the payload will be integrated into a commercially provided 6U bus to transmit and receive data, commands, and telemetry between the satellite and the MC3 network. The spacecraft reference design included two other payloads and used the Astro Digital Corvus-6 bus as the baseline for defining payload-bus-ground interfaces. This project utilized MATLAB Simulink to program the SDR. The SDR will primarily operate in the store-and-forward mode for transmissions when in line-of-sight of a ground station. The up/down convert board was designed, and manufacturing options were explored. Additionally, this project finalized the mechanical enclosure and bus interfaces. The payload aimed to maintain a 0.5U CubeSat form-factor and achieve a data rate of up to 10 Mbps with 1e-5 bit error rate. Following design and construction, the hardware and software components were subjected to functional end-to-end testing to evaluate performance. Further flight qualification will subject the payload to environmental testing to ensure survivability through launch and the expected low-Earth orbit environment., Lieutenant, United States Navy, Approved for public release. distribution is unlimited

3Cat-NXT is a 12 unit CubeSat project developed in the Nanosatlab department of the Universitat Politècnica de Catalunya which main mission is to measure the Earth?s surface soil moisture every three days for at least 3 years. The CubeSat is formed by different subsystems that are being developed to be ready if a launch opportunity comes. This work focuses on the communications subsystem. This thesis is the continuation of the design of the X-band communications subsystem started in the PAE subject of Spring 2020 semester. The work includes the design description, test and characterization of the different parts that form the subsystem that have been performed and modified from the initial design. This parts are the reception amplification stage, the transmission amplification stage, the frequency shifting stage, the digital stage and the power supply. The tests will validate the design performed and quantify the performance of each of the parts that form the communications subsystem., 3CAT-NXT es un proyecto de un CubeSat de 12 unidades desarrollado por el grupo Nanosatlab de la Universitat politècnica de Catalunya que tiene como misión principal medir la humedad superficial de la Tierra cada tres días y como mínimo durante 3 años. El CubeSat está formado por diferentes subsistemas que están siendo desarrollados para tenerlos listos para cuando haya una oportunidad de lanzamiento. Éste trabajo se centra en el subsistema de comunicaciones. Éste trabajo fin de grado es la continuación del diseño del subsistema de comunicaciones en banda X empezado en la asignatura PAE del semestre de primavera de 2020. El trabajo se centra en la descripción, testeo y caracterización de las diferentes partes que forman el subsistema que han sido implementadas y modificadas a partir del diseño inicial. Éstas partes son la etapa de amplificación en recepción, la etapa de amplificación en transmisión, la etapa de cambio de frecuencia, la etapa digital y el suministro de potencia. Los test servirán para validar el diseño desarrollado y cuantificar el rendimiento de cada parte que forma el subsistema de comunicaciones., 3CAT-NXT és un projecte d'un CubeSat de 12 unitats desenvolupat al grup Nanosatlab de la Universitat politècnica de Catalunya que té com a missió principal mesurar la humitat superficial de la Terra cada tres dies durant com a mínim 3 anys. El CubeSat està format per diferents subsistemes que estan sent desenvolupats per ternir-los llestos per quan hi hagi una oportunitat de llençament. Aquest treball es centra en el subsistema de comunicacions. Aquest treball final de grau és la continuació del disseny del subistema de comunicacions en banda X començat a l'assignatura PAE del quatrimestre de primavera de 2020. El treball se centra en la descripció, testeig i caracterització de les diferents parts que formen el subsistema que s'han implementat i modificat a partir del disseny inicial. Aquestes parts són l'etapa l'amplificació en recepció, l'etapa d'amplificació en transmissió, l'etapa de canvi de freqüència, l'etapa digital i el subministrament de potència. Els tests serviran per validar el disseny desenvolupat i quantificaran el rendiment de cada part que forma el susbistema de comunicacions.

A compact quad-band circularly polarized (CP) G-shaped printed antenna with square slot is proposed in this paper. Two semicircular notches have been etched from lower periphery of the ground to increase the impedance bandwidth (IBW). In order to increase significantly the axial ratio bandwidth (ARBW), a spring-shaped notch is etched from the upper periphery of the ground. For further increase of ARBW and better impedance matching, another notch is etched from G-shaped radiating element. The proposed design exhibits simulated IBW = 22.046 GHz (8.954–31 GHz) with the center frequency fc = 20 GHz, and the measured IBW below –10 dB is from 8.8376 to 20 GHz. The IBW above 20 GHz are not measured due to limitations of the available VNA. The ARBW are 306.3 MHz (fc = 11.6 GHz), 363.1 MHz (fc = 21.3 GHz), 380.7 MHz (fc = 27.6 GHz), and 332.2 MHz (fc = 28.6 GHz), which are within the range of IBW. The maximum simulated peak gain is 5.46 dBi at 25.7 GHz. The proposed antenna is suitable for applications in the X-, K- and Ka-bands in the field of wireless communication.

A circularly polarized (CP) CPW-fed (CoPlanar Waveguide) with two asymmetric U-shaped strips, patch antenna is described in this paper. The antenna consists of a radiating patch composed of a hexagonal-ring connected with two annular rings on the two corners, which provide wide CP. The CPW-fed antenna was constructed by etching out two L-shaped slots and adding two asymmetric U-shaped strips to the ground, which greatly enhanced both the impedance bandwidth (IBW) and axial ratio bandwidth (ARBW). The proposed antenna design yields a measured wide IBW = 5.637 GHz (4.484–10.121 GHz), which is about 80.53% with respect to the center frequency fc = 7.3 GHz. The simulated 3-dB axial ratio (AR) bandwidth for tri bands includes 95 MHz (1.37%), 186 MHz (2.35%) and 149 MHz (1.67%) resonating at 6.95, 7.93, and 8.91 GHz, respectively. The radiation characteristics of the implemented antenna have been analyzed and discussed in this paper. The maximum simulated peak gain is 5.968 dBi at 6.063 GHz. The proposed antenna can be suitable for C- and X-band wireless communication applications.

Discharge forecasting is a key component for early warning systems and extremely useful for decision makers. Forecasting models require accurate rainfall estimations of high spatial resolution and other geomorphological characteristics of the catchment, which are rarely available in remote mountain regions such as the Andean highlands. While radar data is available in some mountain areas, the absence of a well distributed rain gauge network makes it hard to obtain accurate rainfall maps. Thus, this study explored a Random Forest model and its ability to leverage native radar data (i.e., reflectivity) by providing a simplified but efficient discharge forecasting model for a representative mountain catchment in the southern Andes of Ecuador. This model was compared with another that used as input derived radar rainfall (i.e., rainfall depth), obtained after the transformation from reflectivity to rainfall rate by using a local Z-R relation and a rain gauge-based bias adjustment. In addition, the influence of a soil moisture proxy was evaluated. Radar and runoff data from April 2015 to June 2017 were used. Results showed that (i) model performance was similar by using either native or derived radar data as inputs (0.66 < NSE < 0.75; 0.72 < KGE < 0.78). Thus, exhaustive pre-processing for obtaining radar rainfall estimates can be avoided for discharge forecasting. (ii) Soil moisture representation as input of the model did not significantly improve model performance (i.e., NSE increased from 0.66 to 0.68). Finally, this native radar data-based model constitutes a promising alternative for discharge forecasting in remote mountain regions where ground monitoring is scarce and hardly available.

A novel compact bowtie slotted circular patch antenna with quad-band notched characteristics is demonstrated in this work. The presented prototype is ascertained on FR-4 substrate. Initially, an Ultra-Wideband (3.1-10.6 GHz) antenna is achieved. Later, undesirable bands between 3.55-5.16, 5.52-5.73, 6.44-6.78 and 7.61-10.6 GHz are eliminated by incorporating slots in the patch. By proper optimization of the patch as well as ground plane, four resonant bands are achieved between 2.56-3.53, 5.22-5.5, 5.7-6.4 and 6.81-7.53 GHz supporting LTE2500, WiMAX, WLAN, and X-band applications. For good impedance matching, the antenna employs a very unique bat-shaped defected ground plane structure. The peak gain of 3.7 dB is obtained by the proposed radiator. A good agreement is observed between the measured and simulated results., QC 20200123

Bathymetry strongly affects nearshore hydrodynamics that drive sediment transport. However, recent bed level information is not always available, especially not simultaneously resolved in space and time. Time series of radar backscatter images can be used to retrieve bed levels in the intertidal area with the so-called Temporal Waterline Approach (TWA) by Bell et al. [2016], yielding a two weeks average bathymetry at spatial resolutions in the order of a few meters. Bed levels are estimated for each radar cell individually by correlating temporal patterns of wet-dry transitions from the radar with hypothetical patterns found in the water level record for different tidal levels. In this study data recorded by a marine X-band radar located at Bunker Hill station (Sylt, German Wadden Sea island) is used to improve TWA, validate the improvement as well as to show its potential in application. A survey was conducted in May 2018 to provide ground truth. Two modifications are made, that improve robustness and reliability of TWA’s output by adding a second threshold and semi-automating the quality procedure. Root mean square error between radar-derived bathymetry (RDB) and ground truth for the intertidal area is 43 cm (bias 12 cm) on a 7.5 m squared grid. Sensitivity analysis of four parameters (i.e. vertical resolution, inclusion of wave induced effects on water level, length and position of analysis window, thresholds in quality check) reveals, that TWA is most sensitive to the choice of thresholds. Sensitivity analysis is utilized to tune TWA to achieve full coverage of the intertidal area (zero coverage elsewhere) with sufficient accuracy. Additionally it is found that at costs of accuracy the period for which averaged bed levels are retrieved can be shortened from 14.5 to 8.3 days. This is promising, because RDB potentially is able to observe short-term changes in the order of a few days (e.g. storm events). To demonstrate the value of the improved TWA for bathymet, Civil Engineering

Software-defined radios (SDRs) are used in many communications applications and offer flexibility in designing a communication network by offering rapid configuration changes after the radio is already produced. This is of interest in the small satellite industry, where small, lightweight, low-cost, and programmable radios will be needed for a wide array of upcoming missions of increasing complexity. Previous Naval Postgraduate School (NPS) research has produced a C-band SDR payload in a 1U CubeSat form factor. The X-band of the radio frequency spectrum offers more bandwidth, and opens the possibility of higher data rate transmissions. The objective for this project was to build an X-band SDR that can be used in future NPS research and flown on multiple platforms, including high altitude balloons, high altitude rockets, and CubeSats. This project built on previous C-band SDR research by converting the transmissions to X-band, expanding the over-air software protocol, implementing a new waveform, increasing the over-air data rate, and assessing the overall performance of the system., DoD Space, http://archive.org/details/xbandsoftwaredef1094563431, Outstanding Thesis, Lieutenant Commander, United States Navy, Approved for public release; distribution is unlimited.

With traditional radio frequency (RF) bands becoming congested and the Department of Defense (DoD) expanding its efforts in the field of small satellites, the need for an on-orbit software-defined radio (SDR) has emerged. SDRs are a compact, off-the-shelf, low-cost, low-risk options for small satellite communication and can provide the flexibility of on-orbit configurability. This study includes the research toward the development of an on-orbit SDR CubeSat payload that can transmit on X-band spectrum (8–12 GHz). This band of interest can provide higher data rates and more bandwidth. Work in CubeSat transmitters and receivers supports development of national capabilities in space of benefit to warfighters. The payload designed, built, and tested for this research is called Com-Cube. Com-Cube utilizes hardware components and software considered for incorporation into a future CubeSat payload. Com-Cube was tested on a low altitude balloon (LAB) flight and demonstrated the transmission of images taken in-flight to a ground station via an amateur radio C-band frequency (5.75 GHz). This work directly supports a transmitter and receiver needed for future telemetry, tracking, and command (TT&C) and payload applications in the field of small satellites. This type of payload provides a test platform for further NPS research in the Mobile CubeSat Command and Control (MC3) ground station network operations and broadcast and receive experiments at frequencies of interest., http://archive.org/details/softwaredefinedr1094561218, Outstanding Thesis, Lieutenant, United States Navy, Approved for public release; distribution is unlimited.

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This article presents the digital baseband receiver for signals from the EOS-PM-1 X-band Earth observing satellite. The conventional SDR is used to provide samples of the baseband signal. The MATLAB software is used for simulating the O-QPSK satellite signal in baseband, algorithms for the Doppler frequency shift and additional frequency offset removal, carrier phase synchronization, symbol timing synchronization and the phase ambiguity removal.

This article presents the digital baseband receiver for signals from the EOS-PM-1 X-band Earth observing satellite. The conventional SDR is used to provide samples of the baseband signal. The MATLAB software is used for simulating the O-QPSK satellite signal in baseband, algorithms for the Doppler frequency shift and additional frequency offset removal, carrier phase synchronization, symbol timing synchronization and the phase ambiguity removal.

This article presents the digital baseband receiver for signals from the EOS-PM-1 X-band Earth observing satellite. The conventional SDR is used to provide samples of the baseband signal. The MATLAB software is used for simulating the O-QPSK satellite signal in baseband, algorithms for the Doppler frequency shift and additional frequency offset removal, carrier phase synchronization, symbol timing synchronization and the phase ambiguity removal.

This article presents the digital baseband receiver for signals from the EOS-PM-1 X-band Earth observing satellite. The conventional SDR is used to provide samples of the baseband signal. The MATLAB software is used for simulating the O-QPSK satellite signal in baseband, algorithms for the Doppler frequency shift and additional frequency offset removal, carrier phase synchronization, symbol timing synchronization and the phase ambiguity removal.

Despite many efforts of the radar community, quantitative precipitation estimation (QPE) from weather radar data remains a challenging topic. The high resolution of X-band radar imagery in space and time comes with an intricate correction process of reflectivity. The steep and high mountain topography of the Andes enhances its complexity. This study aims to optimize the rainfall derivation of the highest X-band radar in the world (4450 m a.s.l.) by using a random forest (RF) model and single Plan Position Indicator (PPI) scans. The performance of the RF model was evaluated in comparison with the traditional step-wise approach by using both, the Marshall-Palmer and a site-specific Z−R relationship. Since rain gauge networks are frequently unevenly distributed and hardly available at real time in mountain regions, bias adjustment was neglected. Results showed an improvement in the step-wise approach by using the site-specific (instead of the Marshall-Palmer) Z−R relationship. However, both models highly underestimate the rainfall rate (correlation coefficient < 0.69; slope up to 12). Contrary, the RF model greatly outperformed the step-wise approach in all testing locations and on different rainfall events (correlation coefficient up to 0.83; slope = 1.04). The results are promising and unveil a different approach to overcome the high attenuation issues inherent to X-band radars.

An X-band high-power amplifier (HPA) based on gallium nitride (GaN) high electron mobility transistors (HEMTs) has been developed for synthetic aperture radar (SAR) applications. A hybrid power combining technique, including microstrip circuits and waveguides, is used to design the HPA. For reducing the size, four 50 W GaN HEMTs cascaded with one 1-to-4 power divider and one 4-to-1 power combiner form a 4-way power combined PCB circuits. For combing the high power and driving an antenna, two PCB circuits are combined by magic-T waveguides. The transmission efficiency of the power combining is approximately 80%. In the 10% duty cycle (pulse width 100 us), the output power of the HPA is over 200 W across the band of 9.5–9.8 GHz. The maximum output power is 230 W at 9.5 GHz, and the power gain is 8.3 dB at 46.1°C.

This paper presents the electromagnetic wave (EW) absorption properties in terms of complex permittivity and permeability of novel green composites coconut fiber coir and charcoal powder materials. The samples were fabricated using the raw agricultural waste coconut fiber coir, charcoal powder, epoxy resin and hardener with varied composition. The dielectric properties of the materials were characterized using two-port waveguide measurement method over the X-band frequency (8.2 – 12.4GHz). The average permittivity value measured is approximately 3.00 with 10wt% charcoal has the highest permittivity of 3.59. Apart from that, all samples exhibit good reflection loss of better than -25dB which means more than 99% absorption rate. The result shows the composite material is a promising organic material for electromagnetic absorber applications.

В дисертаційній роботі розроблено метод об’єднання об’ємних металевих резонансних структур з планарною підкладинкою генератора, що дозволяє значно знизити рівень фазового шуму за рахунок застосування резонаторів зі збільшеними значеннями добротності. Вдосконалено метод проектування двотактних генераторів шляхом використання в якості корисного вихідного сигналу третьої гармоніки основного коливання, що дозволяє досягти низьких рівнів фазового шуму у сантиметровому та міліметровому діапазонах. Розроблено високодобротні моделі резонансних структур, на основі яких побудовано та досліджено нові високотехнологічні конструкції генераторів та синтезаторів зі зниженим рівнем фазового шуму у сантиметровому та міліметровому діапазонах довжин хвиль., The effect of phase noise of local oscillators of frequency converters on the performance of data transmission channels with digital modulation techniques N-PSK and N-QAM is analyzed in the thesis. A method for combining metallic cavity resonance structures with planar oscillator substrate is developed. It significantly reduces the phase noise due to the use of resonators with high quality factors while preserving the planarity of the structure. Push-push design method of oscillators is improved by using the third harmonic of the fundamental oscillation as a useful output, which is achieved by replacing the output circuit of the oscillator and allows reaching low phase noise levels in the centimeter and millimeter bands. The models of resonant structures based on microstrip transmission line, suspended microstrip line, substrate integrated waveguide and cavity rectangular waveguide resonators are developed. They are characterized by high values of quality factor (68—2978). On their basis, and using the proposed improvement of push-push oscillator design method the high-tech designs of planar and quasiplanar osillators were made. The oscillators are characterized by reduced levels of phase noise in the centimeter and millimeter wavelengths, RMS phase of the output signal reaches 0,84º in the millimeter range (phase noise of –96,4 dBc/Hz at offset 10 kHz from the carrier frequency of 36 GHz). A method for calculating the level of oscillator phase noise, which consists in combining Finite-Difference Time-Domain method and the method of Harmonic Balance, is proposed. The method is characterized by high accuracy, which is confirmed by discrepancies with the experimental data within +/– 5 dB. Frequency synthesizers have been developed basing on a push-push VCOs with the ouput at the second (24 GHz) and the third (36 GHz) harmonics, and the VCO integrated circuits (9,9—11,28 GHz), which are thermally stabilized suitable for mass production devices, have low levels of the i, В диссертационной работе разработан метод объединения полых металлических резонансных структур с планарной подложкой генератора, что позволяет значительно снизить уровень фазового шума за счет применения резонаторов с повышенными значениями добротности. Усовершенствован метод проектирования двухтактных генераторов путем использования в качестве полезного выходного сигнала третьей гармоники основного колебания, что позволяет достигнуть низких уровней фазового шума в сантиметровом и миллиметровом диапазонах. Разработаны высокодобротные модели резонансных структур, на основе которых построены и исследованы высокотехнологичные конструкции генераторов и синтезаторов со сниженными уровнями фазового шума в сантиметровом и миллиметровом диапазонах длин волн.

För övervakning av svenska vatten krävs noggranna mätningar av oceanografiska parametrar såsom våghöjd, vågriktning, ytvattentemperatur och ytströmmar. Mätdata för parametrarna samlas in av Sveriges Meteorologiska och Hydrologiska Institut (SMHI) och används till prognoser, sjöfart samt forskning. I denna studie undersöktes möjligheten att ersätta eller komplettera vågbojarna av modellen Directional Waverider MkIII som SMHI använder idag, med ny kommersiellt tillgänglig fjärranalysteknik. Projektet begränsades till att studera två högfrekvens-radartekniker och en X-bandradar. Studien är platsspecifik och utreder kvalitetsmässiga, ekonomiska och miljömässiga för- och nackdelar med de utvalda radarteknikerna i relation till vågbojarna. En litteraturstudie och modellering av data över parametrar som påverkar radarteknikernas räckvidd och datatillgänglighet genomfördes. Ur modelleringen drogs slutsatsen att det är möjligt att erhålla likvärdig datatillgänglighet med vågradar som med vågboj. Vidare modellering ledde till slutsatsen att radarteknikerna begränsas till ungefär hälften av sin optimala räckvidd i Östersjön på grund av den låga salthalten, och därför är Sveriges västkust bättre lämpad för placering av radarteknik. Undersökning av isbildning i havsvatten, som kan begränsa radarteknikernas räckvidd, ledde till slutsatsen att Sveriges västkust också är att föredra utifrån detta perspektiv. Med anledning av radarteknikers möjlighet att utföra mätningar över större områden, finner studien att det finns goda grunder för att motivera en ersättning eller komplettering av vågbojarna med modern radarteknik. Vidare talar radarteknikernas goda anpassningsförmåga, lägre inverkan på miljön och enklare underhållskrav jämfört med vågbojarna till dess fördel. Att övergå till radarteknik medför däremot högre installations- och driftkostnader i jämförelse med vågbojar.

Proyecto a realizar durante estancia en la EPFL, This project describes the process of design and manufacturing of an X-Band (7.1-8.5 GHz) antenna for a CubeSat satellite, facing many of the design criteria and challenges of pico-satellites. A CubeSat is a type of miniaturized satellite for space research that is made up of multiples of 10×10×10 cm cubic units and has a mass of no more than 1.33 kilograms per unit. It can be manufactured using commercial off-the-shelf (COTS) components for its electronics and structure. Limited size, low mass, circular polarization, high gain and wide bandwidth are the main challenges of the antenna design. A design of an aperture-coupled patch antenna has been performed to overcome the difficulties and fulfill all the requirements for CubeSats antennas. The antenna consists of one or two rectangular patches, fed by a microstrip line through a crossed slot in the ground plane. The two patches are separated from the ground plane using a layer of hard, low-permittivity foam. After the study of several antenna models, a stacked patch antenna (two patches) accomplished most of the requirements. The antenna models have been simulated using a 3-D electromagnetic simulation software, HFSS. Simulation and measured results show a gain within 6-10dB, very good circular polarization, a good matching in the whole frequency band and accomplish dimension criterias for CubeSat antennas., Este proyecto describe el proceso de diseño y fabricación de una antena X-Band (7.1-8.5 GHz) para un satélite CubeSat, frente a muchos de los criterios de diseño y desafíos de los picosatélites. CubeSat se trata de un satélite miniaturizado, dedicado a la investigación espacial que está compuesto por múltiples unidades cúbicas de dimensiones 10 × 10 × 10 $\mathrm{cm}^3$ y con una masa no superior a 1.33 kilogramos la unidad. Este puede ser fabricado usando componentes comerciales (COTS) para su composición electrónica y estructural. En el tamaño reducido, su baja masa, su polarización circular, la alta ganancia del dispositivo y en el amplio ancho de banda se encuentran los principales desafíos del diseño de la antena. Se ha realizado un diseño de una \textit{patch} antena para superar las dificultades y satisfacer todos los requisitos del diseño. La antena consta de dos \textit{patch} rectangulares, alimentadas por una línea microstrip a través de una ranura cruzada en el respectivo plano de masa. Ambas \textit{patch} están separadas de la alimentación y el plano de masa mediante una capa de espuma dura de baja permitividad dieléctrica. Después del estudio de varios modelos de antena la compuesta por dos \textit{patch} ha satisfecho los requisitos necesarios. Los modelos de antena han sido diseñados utilizando un software de simulación electromagnético 3-D, HFSS. Los resultados tanto simulados como medidos muestran una ganancia entre 6-10 dB, una muy buena polarización circular, y buena adaptación en todo el rango de frecuencias, todo ello cumpliendo con las dimensiones limitadas de una antena para un CubeSat., Aquest projecte descriu el procés de disseny i fabricació d'una antena X-Band (7.1-8.5 GHz) per un satèl·lit CubeSat, davant molts dels criteris de disseny i desafiaments dels picosatèl·lits. CubeSat es tracta d'un satèl·lit miniaturitzat dedicat principalment a la investigació espacial que està compost per múltiples unitats cúbiques de dimensions 10 × 10 × 10 $\mathrm{cm}^3$ i amb una massa no superior a 1,33 quilograms la unitat. Aquest pot ser fabricat utilitzant components comercials (COTS) per a la seva composició electrònica i estructural. La mida reduïda, la seva baixa massa, la seva polarització circular, l'alt guany del dispositiu i l'ampli ample de banda composen els principals reptes del disseny de l'antena. S'ha realitzat un disseny d'una \textit{patch} antena per superar les dificultats i complir tots els requisits del disseny. L'antena consta de dues \textit{patch} rectangulars, alimentades per una línia microstrip a través d'una ranura creuada en el respectiu pla de massa. Les dues \textit{patch} estan separades de l'alimentació i el pla de massa mitjançant una capa d'espuma dura de baixa permitivitat dielèctrica. Després de l'estudi de diversos models d'antena la composta per dos \textit{patch} ha proporcionat els millors resultats tenint en compte els requisits de l'antena. Els models d'antena han estat dissenyats utilitzant un programa de simulació electromagnètica en 3-D, HFSS. Els resultats tant de simulació com mesurats, mostren un guany entre 6-10 dB, una molt bona polarització circular i una bona adaptació en tot el rang de freqüències cumplint amb els criteris de tamany limitat per antenes CubeSat.

A e+e- collider of several TeV energy will be needed for the precision studies of any new physics discovered atthe LHC collider at CERN. One promising candidate is CLIC, a linear collider which is based on a two-beam acceleration scheme that efficiently solves the problem of power distribution to the acceleration structures. The phenomenon that currently prevents achieving highaccelerating gradients in high energy accelerators such asthe CLIC is the electrical breakdown at very high electrical field.The ongoing experimental work within the CLIC collaboration is trying to benchmark the theoretical models focusing on the physics of vacuum breakdown which is responsible for the discharges. In order to validate the feasibility of accelerating structures and observe the characteristics of the vacuum discharges and their eroding effects on the structure two dedicated spectrometers are now commissioned at the high-power test-stands at CERN. First, the so called Flashbox has opened up a possibility for non-invasive studies of the emitted breakdown currents during two-beam acceleration experiments. It gives an unique possibility to measure the energy of electrons and ions in combination withthe arrival time spectra and to put that in context with accelerated beam, which is not possible at any of the other existing test-stands.The second instrument, a spectrometer for detection of the dark and breakdown currents, is operated at one of the 12 GHz stand-alone test-stands at CERN. Built for high repetition rate operation it can measure the spatial and energy distributions of the electrons emitted from the acceleration structure during a single RF pulse. Two new analysis tools: discharge impedance tracking and tomographic image reconstruction, applied to the data from the spectrometer make possible for the first time to obtain the location of the breakdown inside the structure both in the transversal and longitudinal direction thus giving a more complete picture of the vacuum

Ocean surface waves propagate according to a dispersion relationship, which defines the relationship between a wave’s wavenumber and its frequency. In the presence of underlying currents, waves are accelerated or decelerated, and this dispersion relationship is augmented by an additional Doppler shift. Furthermore, if the underlying currents are not depth-uniform, the Doppler shift-wavenumber relationship is non-linear. This dissertation focuses on the development of an inversion method to estimate current-depth profiles from a collection of wavelength-dependent Doppler shift measurements. This process leverages Gaussian quadrature along with multiple least squares techniques to supply constraints to the otherwise inherently noisy inversion. To measure Doppler shifts to be used as inputs into the inversion process, this work takes advantage of the sensitivity of marine X-band backscatter to space-time wavefield properties. Sequential images of backscatter are collected and, using a Fast Fourier Transform, are transformed into wavenumber-frequency space for current extraction.X-Band backscatter (along with supporting wind and current measurements) was collected during two unique field campaigns. The first took place in June, 2013 as a part of the Riverine and Estuarine Transport Experiment 2 (RIVET2) field campaign in the Mouth of the Columbia River (MCR), Oregon. The second data set was collected from R/P FLIP in the Southern California bight in November 2013 as a part of the SoCal2013 experiment. From the strong, polarized currents in the MCR to the weaker, wind- and tide-driven currents of the deeper water off of California, the contrast between the data sets from the perspective of wave-current interaction is significant. The results of the new inversion method from both data sets are compared to those measured by ADCPs. The depth- and time-dependence of the comparisons show that inverted currents successfully capture important geophysical phenomena such as depth

The Generalized Likelihood Uncertainty Estimation methodology (GLUE) is investigated for radar rainfall calibration and uncertainty assessment. The method is used to calibrate radar data collected by a Local Area Weather Radar (LAWR). In contrast to other LAWR data calibrations, the method combines calibration with uncertainty estimation. Instead of searching for a single set of calibration parameters, the method uses the observations to construct distributions of the calibration parameters. These parameter sets provide valuable knowledge of parameter sensitivity and the uncertainty. Two approaches are analyzed; the static calibration approach, where the LAWR is calibrated once for a long period and the dynamic approach, where the estimate is continuously adjusted based on ground observations. The analysis illustrates that the static calibration performs insufficiently, whereas the dynamic adjustment improves the performance significantly. It is found that even if the dynamic adjustment method is used the uncertainty of rainfall estimates can still be significant.

The goal of this thesis is to create a design of a microwave power amplifier working in X-band at the center frequency of 10.368GHz. The amplifier has to operate in CW mode and pulse mode with output power of 36dBm and gain of 20dB.

The goal of this thesis is to create a design of a microwave power amplifier working in X-band at the center frequency of 10.368GHz. The amplifier has to operate in CW mode and pulse mode with output power of 36dBm and gain of 20dB.

The goal of this thesis is to create a design of a microwave power amplifier working in X-band at the center frequency of 10.368GHz. The amplifier has to operate in CW mode and pulse mode with output power of 36dBm and gain of 20dB.

The goal of this thesis is to create a design of a microwave power amplifier working in X-band at the center frequency of 10.368GHz. The amplifier has to operate in CW mode and pulse mode with output power of 36dBm and gain of 20dB.

The goal of this thesis is to create a design of a microwave power amplifier working in X-band at the center frequency of 10.368GHz. The amplifier has to operate in CW mode and pulse mode with output power of 36dBm and gain of 20dB.

Diplomová práce je zaměřena na využití plošné Antény Yagi-Uda v pásmu X. Teoretická část se zaměřuje na popis vlastností antén a princip antény Yagi-Uda. Je zde vysvětleno dělení výkonu a vlastnosti výpočetní metody FDTD. V praktické části je popsán postup návrhu antény Yagi-Uda a osmiprvkové anténní řady. Byl navržen model v prostředí CST Microwave Studio pro jeden prvek Yagi-Uda a pro osmiprvkovou anténní řadu. Oba modely byly vyrobeny a provedlo se jejich měření., The thesis is focused on utilization of planar Yagi-Uda antenna in the X-Band. The theoretical part is focused on the description of the features of antennas and the principle of Yagi-Uda antenna. It explains the power division and FDTD computational method. The practical part describes the design of the Yagi-Uda antenna and the eight-elemental antenna array. A model was designed in an CST Microwave Studio environment for one element Yagi-Uda antenna and eight-elemental antenna array. Both models have been produced and the measurements were performed., Katedra elektrotechniky, Cílem práce bylo navrhnout anténní řadu v pásmu 9 - 10 GHz, složenou z plošných prvků typu Yagi-Uda a na laboratorním vzorku ověřit její parametry. Práce se skládá ze čtyř základních částí: v kap. 2 a 3 jsou popsány základní vlastnosti antén a děličů výkonu, v kap. 4 je uveden popis funkce výpočetního prostředku CST Studio Suite, kap. 5,6,7, jsou věnovány návrhu vyzařovacího prvku a antény a v kap. 8 je popsána realizace vzorků jednotlivých částí i celé anténní řady a výsledky měření jejich parametrů. Náplň diplomové práce byla poměrně náročná: vyžadovala znalosti z oblasti teorie obvodů s rozloženými parametry a základních vlastností antén a současně z oblasti metod modelování a výpočtu elektromagnetického pole v komplikovaném prostředí a metod měření parametrů mikrovlnných obvodů a antén. Diplomant ověřil správnost návrhu měřením parametrů zhotovených laboratorních vzorcích děličů výkonu, anténních elementů i celé anténní řady. Zhotovený vzorek dosáhl vcelku dobrých výsledků.

NANOTEC

A X-band GaN monolithic microwave integrated circuits (MMIC) High Power Amplifier (HPA) suitable for future generation Synthetic Aperture Radar systems is presented. The HPA delivers 14 W of output power, more than 38% of PAE in the frequency bandwidth from 8.8 to 10.4 GHz. Its linear gain is greater than 25 dB. For the first time an MMIC X-band HPA has been designed by directly measuring the transistor behavior at the current generator plane. In particular, optimum device load-line has been selected according to the chosen performance tradeoffs.

We present arbitrary control over a homogenous spin system, demonstrated on a simple, home-built, electron paramagnetic resonance (EPR) spectrometer operating at 8-10 GHz (X-band) and controlled by a 1 GHz arbitrary waveform generator (AWG) with 42 dB (i.e. 14-bit) of dynamic range. Such a spectrometer can be relatively easily built from a single DAC (digital to analog converter) board with a modest number of stock components and offers powerful capabilities for automated digital calibration and correction routines that allow it to generate shaped X-band pulses with precise amplitude and phase control. It can precisely tailor the excitation profiles "seen" by the spins in the microwave resonator, based on feedback calibration with experimental input. We demonstrate the capability to generate a variety of pulse shapes, including rectangular, triangular, Gaussian, sinc, and adiabatic rapid passage waveforms. We then show how one can precisely compensate for the distortion and broadening caused by transmission into the microwave cavity in order to optimize corrected waveforms that are distinctly different from the initial, uncorrected waveforms. Specifically, we exploit a narrow EPR signal whose width is finer than the features of any distortions in order to map out the response to a short pulse, which, in turn, yields the precise transfer function of the spectrometer system. This transfer function is found to be consistent for all pulse shapes in the linear response regime. In addition to allowing precise waveform shaping capabilities, the spectrometer presented here offers complete digital control and calibration of the spectrometer that allows one to phase cycle the pulse phase with 0.007° resolution and to specify the inter-pulse delays and pulse durations to ≤ 250 ps resolution. The implications and potential applications of these capabilities will be discussed.

A coplanar waveguide (CPW) fed ultra-wideband (UWB) antenna with dual notched band characteristics is presented in this paper. The circular wide slot and circular radiation patch are utilized to broaden the impedance bandwidth of the UWB antenna. The dual notched band functions are achieved by employing two stepped impedance resonators (SIRs) which etched on the circular radiation patch and CPW excitation line, respectively. The two notched bands can be controlled by adjusting the dimensions of the two stepped impedance resonators which give tunable notched band functions. The proposed dual notched band UWB antenna has been designed in details and optimized by means of HFSS. Experimental and numerical results show that the proposed antenna with compact size of 32 × 24 mm2, has an impedance bandwidth range from 2.8 GHz to 13.5 Hz for voltage standing-wave ratio (VSWR) less than 2, except the notch bands 5.0 GHz - 6.2 GHz for HIPERLAN/2 and IEEE 802.11a (5.1 GHz - 5.9 GHz) and 8.0 GHz - 9.3 GHz for satellite and military applications.

A coplanar waveguide (CPW) fed ultra-wideband (UWB) antenna with dual notched band characteristics is presented in this paper. The circular wide slot and circular radiation patch are utilized to broaden the impedance bandwidth of the UWB antenna. The dual notched band functions are achieved by employing two stepped impedance resonators (SIRs) which etched on the circular radiation patch and CPW excitation line, respectively. The two notched bands can be controlled by adjusting the dimensions of the two stepped impedance resonators which give tunable notched band functions. The proposed dual notched band UWB antenna has been designed in details and optimized by means of HFSS. Experimental and numerical results show that the proposed antenna with compact size of 32 × 24 mm2, has an impedance bandwidth range from 2.8 GHz to 13.5 Hz for voltage standing-wave ratio (VSWR) less than 2, except the notch bands 5.0 GHz - 6.2 GHz for HIPERLAN/2 and IEEE 802.11a (5.1 GHz - 5.9 GHz) and 8.0 GHz - 9.3 GHz for satellite and military applications.

A coplanar waveguide (CPW) fed ultra-wideband (UWB) antenna with dual notched band characteristics is presented in this paper. The circular wide slot and circular radiation patch are utilized to broaden the impedance bandwidth of the UWB antenna. The dual notched band functions are achieved by employing two stepped impedance resonators (SIRs) which etched on the circular radiation patch and CPW excitation line, respectively. The two notched bands can be controlled by adjusting the dimensions of the two stepped impedance resonators which give tunable notched band functions. The proposed dual notched band UWB antenna has been designed in details and optimized by means of HFSS. Experimental and numerical results show that the proposed antenna with compact size of 32 × 24 mm2, has an impedance bandwidth range from 2.8 GHz to 13.5 Hz for voltage standing-wave ratio (VSWR) less than 2, except the notch bands 5.0 GHz - 6.2 GHz for HIPERLAN/2 and IEEE 802.11a (5.1 GHz - 5.9 GHz) and 8.0 GHz - 9.3 GHz for satellite and military applications.

This paper reports on design, fabrication, and characterization of a novel multistage all-silicon microwave MEMS phase-shifter concept, based on multiple-step deep-reactive-ion-etched monocrystalline-silicon dielectric blocks which are transfer bonded to an RF substrate containing a 3-D micromachined coplanar waveguide. The relative phase shift of 45 degrees of a single stage is achieved by vertically moving the lambda/2-long blocks by MEMS electrostatic actuation. The measurement results of the first prototypes show that the return and insertion loss of a 7 x 45 degrees multistage phase shifter over the whole frequency spectrum from 1 to 110 GHz are better than -12 and -5.1 dB, respectively. The monocrystalline high-resistivity silicon blocks are acting as a dielectric material from an RF point of view, and at the same time as actuation electrodes for dc electrostatic actuation. The mechanical reliability was investigated by measuring life-time cycles. All tested phase shifters with three-meander 36.67-N/m mechanical spring and a pull-in voltage of 29.9 V survived 1 billion cycles after which the tests were discontinued, no indication of dielectric charging could be found, neither caused by the dielectric block nor by the Si3N4 distance keepers to the bottom electrodes. Finally, it is investigated that, by varying the fill factor of the etch hole pattern, the effective dielectric constant of the block can be tailor made, resulting in 45 degrees, 30 degrees, and 15 degrees phase-shifter stages fabricated out of the same dielectric material by the same fabrication process flow. [2009-0201], QC 20100525