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A four-element multiple-input-multiple-output (MIMO) antenna has been designed to operate at triple wide bands with improved port-isolation and polarisation diversity. The resonant modes of the MIMO are achieved by meander slot-loaded elliptical-shaped fundamental radiators, and the inter-port isolation is achieved by employing neutralising line-embedded ground plane. Apart from port-isolation, the proposed MIMO also offers polarisation diversity at different operating bands. The triple-band MIMO offers linear polarised radiation at WLAN band (4.2–5.6 GHz), right-hand circular polarised (RHCP) radiation at C-band (6.3–7.5 GHz) and left-hand circular polarised (LHCP) radiation at X-band (8.7–9.3 GHz). The overall isolation (>27 dB), envelope correlation co-efficient (ECC<0.0005), diversity gain (DG>9.9995), mean effective gain (MEG<0.734 dB), total active reflection co-efficient (TARC<−20 dB) and channel capacity loss (CCL<0.35 bits/S/Hz) meet the criteria for reliable MIMO operation. The proposed MIMO has been fabricated on a 55.6 × 55.6 × 1.6 mm3 piece of an FR-4 epoxy substrate after simulation and measured in VNA. Adequate similarity can be observed between the measured and simulated results. [ABSTRACT FROM AUTHOR]

The electromagnetic interference (EMI) shielding effectiveness of the epoxy polymer composite reinforced with carbon fiber mat (CFM), short carbon fiber (SCF), and multi‐walled carbon nanotube (MWCNT) is studied in the X‐band (8–12 GHz). Single‐layer unidirectional CFM of 30 wt% epoxy composite with 0° and 90° orientations resulted in EMI shielding of 5 dB and 29.6 dB, respectively. To avoid the influence of CFM orientation on the EMI shielding, SCF of distinct weight percentages (1 and 5 wt%) with fixed weight percentage (1 wt%) of MWCNT are reinforced into epoxy matrix. The EMI shielding provided by 2 mm thick epoxy composite reinforced with 5 wt% SCF along with 1 wt% MWCNT (CNT‐SCF5) is 35.4 dB. The microstructural study revealed uniform dispersion and better adhesion of MWCNT and SCF in the epoxy matrix. The dielectric properties of the fabricated samples indicated an increase in permittivity, electrical tanδ, and conductivity with the grading of SCF and MWCNT. The mechanical properties such as tensile strength and strain of the CNT‐SCF5 showed an increment in ultimate tensile strength and Young's modulus. The homogeneous CNT‐SCF5 epoxy composite with enhanced EMI shielding ability and mechanical properties could be utilized as an efficient EMI shielding material. [ABSTRACT FROM AUTHOR]

In this article, a dual circularly polarized high gain superstrate integrated X‐band antenna is designed and analyzed for CubeSat applications. The proposed antenna consists of a metallic patch, multilayer space qualified printed circuit boards, and a dielectric superstrate with a high relative permittivity on top of the patch to establish a suitable resonance condition for high‐gain operation. The driven patch is fed by a 3‐dB hybrid coupler for the generation of dual (left hand circular polarization and right hand circular polarization) circular polarization. The antenna exhibits an impedance bandwidth of >18.5% (7.75–9.4 GHz) with a peak gain of >16 dBiC. The achieved antenna performance makes it suitable for CubeSat missions at X‐band. [ABSTRACT FROM AUTHOR]

Nowadays, the design of a miniaturised ultra-wideband (UWB) antenna with wide dual band-notched characteristics gained widespread demand in wireless communications to reduce interference. The design of a planar CPW-fed circular UWB antenna loaded with split ring resonators and stubs is presented to eliminate two frequency bands. Two symmetrical circular split ring resonators are etched below the CPW feed at the backside of a circular UWB monopole antenna to suppress 3.61 GHz–5.57 GHz (sub-6 GHz band) wideband interference, whereas the 7.06 GHz–8.79 GHz (X-band uplinks and downlinks) band is suppressed by loading two L-shaped stubs. Slots are also made on the patch and ground to enhance impedance matching at a lower resonance frequency. The proposed notch band antenna has a compact size of 38 × 32 × 1.6 mm3 and has the highest gain of 5.75 dB at a frequency of 9 GHz. The parametric analysis has been performed to obtain optimised dimensions for better performance. The designed antenna is simulated, prototyped and tested to validate the antenna design. [ABSTRACT FROM AUTHOR]

In this dissemination, a glueless compact dual port dielectric resonator antenna (DRA) is proposed for X-band applications. A prototype has been fabricated with RT Duroid substrate and Eccostock ( ϵ r = 10)-made DRA. The ring shaped DRA is excited by aperture coupled feeds maintaining symmetry between both the ports. Four cylindrical copper rods with four strips have been used to fix the DRA on the substrate and provide additional mechanical stability. Eight copper strips are used to provide impedance matching and impedance bandwidth (IBW) widening. The measured IBW of dual port DRA is 10.5% (8.05–8.95 GHz) and maximum gain of radiator is 6.2 dBi. The proposed antenna becomes compact when the net volume of DRA is approximately 3.5 cm 3 and the volume of the substrate is 2.88 cm 3 , with a surface area of 36 cm 2 and operating in X-band, which finds applications in satellite communication, weather radar, synthetic aperture radar, and telemetry tracking and control. [ABSTRACT FROM AUTHOR]

A low-profile single-ridge waveguide magic-T is proposed as a combination of two T-junctions at an X band. A slot coupling technique is used to reduce the component dimensions in the E-plane, thus leading to a low profile. The device can assume two configurations by arranging the sum and difference ports in the same or opposite direction, an attractive feature in the design of beamforming networks with complex routing. A magic-T prototype is fabricated using laser powder bed fusion additive manufacturing techniques. Good agreement between simulations and measurements is found. [ABSTRACT FROM AUTHOR]

In this article, a 4 × 4 miniaturized UWB-MIMO antenna with reduced isolation is designed and analyzed using a unique methodology known as characteristic mode analysis. To minimize the antenna's physical size and to improve the isolation, an arrangement of four symmetrical radiating elements is positioned orthogonally. The antenna dimension is 40 mm × 40 mm (0.42λ0 × 0.42λ0) (λ0 is the wavelength at first lower frequency), which is printed on FR-4 material with a width of 1.6 mm and ε r   = 4.3. A square-shaped defected ground framework was placed on the ground to improve the isolation. Etching square-shaped slots on the ground plane achieved the return losses S11 < −10 dB and isolation 26 dB in the entire operating band 3.2 GHz–12.44 GHz (UWB (3.1–10.6 GHz) and X-band (8 GHz–12 GHz) spectrum and achieved good isolation bandwidth of 118.15%. The outcomes of estimated and observed values are examined for MIMO inclusion factors such as DG, ECC, CCL, and MEG. The antenna's performances, including radiation efficiency and gain, are remarkable for this antenna design. The designed antenna is successfully tested in a cutting-edge laboratory. The measured outcomes are quite similar to the modeled outcomes. This antenna is ideal for WLAN and Wi-Max applications. [ABSTRACT FROM AUTHOR]

In this paper, a microstrip patch antenna fed by a waveguide using an end-wall iris through ground plane has been modelled. The iris feed technique was proposed to overcome the narrow bandwidth problem of microstrip patch antenna. The iris is sized so that it is resonant and subsequently the antenna operates under the fusion of two modes relating to the iris and the patch, resulting in a wideband radiation characteristic with dual resonance. Measurement demonstrates the single bandwidth dual resonance type and the radiation bandwidth of (8 GHz-10.6 GHz). In order to show the impact of the iris feed technique on microstrip patch antenna's bandwidth, a comparison with some state-of-the-art works proposing various bandwidth enhancement techniques in the X-band is made. The proposed prototype, with a size of 1.76λ0×1.65λ0×1.29λ0, is more compact than several designs. It has a fractional bandwidth of 27.9%, thus it presents the prototype with the widest bandwidth with the simplest design fabrication. With regard to the electromagnetic modelling, this work is oriented towards the use of the hybrid MOM-GEC method in order to be able to perform a rigorous electromagnetic. It has been found that the MOM-GEC model is more efficient in terms of memory requirements and approximately four times faster than HFSS simulator software. [ABSTRACT FROM AUTHOR]

A Fractal geometry based compact multiband wearable button antenna with wider bandwidth, less cross polarized radiation in both the orthogonal planes and low specific absorption rate (SAR) at all the resonating bands is presented in this article. The antenna comprises a slotted circular patch printed on the top of a circular piece of low-cost FR-4 substrate with radius 9.6 mm fed through coaxial feeding mechanism. Multiband behavior is achieved by the implementation of fractal based circular slots up to third iteration whereas the loading of two additional circular slots offers significant improvement in both bandwidth and gain. Radii of the circular slots are optimized properly in HFSS to attain the desired performance. On-cloth and on-body analyses of the proposed antenna are also carried out to investigate the effect of interaction with cloth and body materials on the antenna performance. The antenna offers multiband response covering the operating bands 4.1–4.64 GHz, 7.19–8.03 GHz and 8.85–9.67 GHz with very low SAR value ensuring less electromagnetic interaction with body tissues. The fabricated prototype shows comparable measured values with the simulated ones. [ABSTRACT FROM AUTHOR]

In this study, the quantitative precipitation estimation (QPE) capability of three X-band dual-polarization phased array radars (PAR) in Guangzhou, South China, was demonstrated, with an S-band operational dual-polarization radar as the benchmark. Rainfall rate (R) estimators based on the specific differential phase (KDP) for summer precipitation for both X-band and S-band radars were derived from the raindrop size distributions (DSDs) observed by a 2-dimensional video disdrometer (2DVD) in South China. Rainfall estimates from the radars were evaluated with gauge observations in three events, including pre-summer rainfall, typhoon precipitation, and local severe convective precipitation. Observational results showed that radar echoes from the X-band PARs suffered much more severely from attenuation than those from the S-band radar. Compared to S-band observations, the X-band echoes can disappear when the signal-to-noise ratio drops to a certain level due to severe attenuation, resulting in different estimated rainfall areas for X- and S-band radars. The attenuation corrected by KDP had good consistency with S-band observations, but the accuracy of attenuation correction was affected by DSD uncertainty and may vary in different types of precipitation. The QPE results demonstrated that the R(KDP) estimator produced better rainfall accumulations from the X-band PAR observations compared to the S-band observations. For both the X-band and S-band radars, the estimates of hourly accumulated rainfall became more accurate in heavier rainfall, due to the decreases of both the DSD uncertainty and the impact of measurement errors. In the heavy precipitation area, the estimation accuracy of the X-band radar was high, and the overestimation of the S-band radar was obvious. Through the analysis of the ZH-ZDR distribution in the three weather events, it was found that the X-band PAR with the capability of high spatiotemporal observations can capture minute-level changes in the microphysical characteristics, which help improve the estimation accuracy of ground rainfall. [ABSTRACT FROM AUTHOR]

A new simple design of an inverted microstrip Gap Waveguide filtering antenna integrated with two stopband filters is proposed in this work. In order to simultaneously provide filtering and radiating functions, we use the direct integration approach to cascade two periodic sets of coplanar coupled EBG resonators with a slot antenna. The analysis shows that the filters can be easily adjusted in the same feeding layer of the antenna, without extra circuitry and without modifying the lines. EBG-filters are compact and offer great flexibility in determining the frequency, width and selectivity of the rejected bands. Experimental results for an X-band filtering antenna prototype are provided showing a 7.3% transmission band centered at 10.2 GHz and a realized gain peak of 2.1 dBi. The measurements demonstrate the filtering capability of the proposed antenna, achieving rejection levels greater than 12 dB and 20 dB for the bands below and above the operation band. The proposed low-complexity design offers good performance as a filter and as an antenna, showing the essential advantages of the Gap Waveguide Technology, including low losses, self-packaging and limited cost. This work demonstrates the possibility of integrating the new coplanar EBG-filters into future Gap Waveguide antenna designs to avoid unwanted radiation, to reduce interfering signals or to provide high isolation in multiband systems. [ABSTRACT FROM AUTHOR]

A novel elliptically slotted antenna (ESA), with two notched bands for Ultrawideband (UWB) applications, is presented. The ESA comprises of an elliptically slotted radiator with a beveled defected ground structure (DGS) for achieving UWB bandwidth ranging from 3.42 to 11.79 GHz (110%) for VSWR< 2. Two rejected bands at WLAN (5.02–5.97 GHz) and down link of X- band (7.23–7.72 GHz) applications are obtained by etching S-shaped slot in the microstrip feed line and an asymmetrical C- shaped parasitic stub above the DGS, respectively. The ESA is printed on FR-4 substrate with a compact size of 24 × 28 m m 2 and with a stable gain fluctuation from 2 to 4.08 dBi. A good matching, achieved in-between tested and simulated results, makes ESA to be a suitable candidate for WLAN/X-band-notched UWB applications. [ABSTRACT FROM AUTHOR]

In this work, substantial increase in electromagnetic (EM) shielding of polystyrene–polyaniline (PS-PANI) composite by way of addition of carbon nanofibers has been achieved. PANI was synthesized through chemical root using chemical oxidative polymerization method. Copolymer of PS with conducting polymer PANI and carbon nanofiber (CF) were prepared using solution mixing method. The synthesized PS-PANI-CF composites were characterized using X-ray diffraction, scanning electron microscopy, and D-shore hardness tester while thermal stability was determined by thermogravimetric analysis. Shielding effectiveness of the composites was investigated in the frequency range of 8.2–12.4 GHz (X-band region) using a vector network analyzer. Synthesized PS-PANI-CF composite exhibits an absorption dominated EM shielding value of 39 dB at 8.4 GHz frequency. [ABSTRACT FROM AUTHOR]

In this article, we demonstrate a low-cost 7.25-7.75 GHz two-stage low noise amplifier with sub-1-dB noise figure for satellite communication applications. The microstrip technology on Rogers RT5880 substrate with the dielectric constant of 2.2 and thickness of 0.508 mm were utilized to develop a low noise amplifier. The printed-circuit-board technology offers a variety of profits such as being low-cost, lighter-weight and re-configurability after the manufacturing process make this technology charming for satellite communication systems for both commercial and military applications. Since the monolithic microwave integrate circuit technology provide much smaller sized circuits and high electrical performance especially at the millimeter-wave frequencies, the printed microstrip technology can be a significant rival to integrated-circuit technology with its proven reliability, easier, cheaper and faster manufacturing process, compactible electrical performance in X-band applications. Moreover, the proposed amplifier was developed with utilizing California Eastern Laboratories' CE3512K2 transistor on Rogers-RT5880 and surface mount devices were utilized in the matching networks to reduce the size. In addition, the source-generation and interstage matching topologies were implemented to simplify the matching complexity to enhance the noise and gain. The prototype was manufactured with utilizing LPKF prototyping machine. The developed LNA exhibits a measured gain of 23.5±0.5 dB with the noise figure of less than 0.9 dB and input/output return loss better than 11.5 dB in the operating frequency bandwidth. Furthermore, the developed amplifier has a measured carrier to interference of-59 dBc and P1dB of 13 dBm at the center frequency while consuming a total DC power of 50 mW. [ABSTRACT FROM AUTHOR]

In this study, a compact U-slot patch antenna design based on dielectric measurement approach of Flame Retardant 4 (FR4) material is presented for X band space applications. In accordance with the design method, the measured frequency dependent dielectric constant and tangent loss values of the FR4 material at X-band using the waveguide method is applied to the HFSS design tool to be used in antenna designs. Then, the functional performance of the design method on antennas is verified by comparing the simulation and measurement results of a conventional antenna design in the literature. In the light of the verified results, a new U-slot patch antenna design with lateral side slots for X-band space applications is presented with a feed line by using the proposed design method. The presented compact antenna design provides 1.77 dB gain at the center frequency (9.5 GHz) and the frequency bandwidth from 8.53 GHz to 10.63 GHz. [ABSTRACT FROM AUTHOR]

A compact printed antenna with three rejected bands has been examined and presented in this manuscript. This antenna is fed by a coplanar waveguide and operates over a wide range of frequencies. An arc-shaped, rectangular strip like and split-ring slot have been etched from the designed radiating patch to generate the rejection peaks at Wi-MAX, WLAN and X-band satellite communication. Primarily, the rectangular patch has been considered and further this patch is modified to acquire the UWB frequency spectrum from 3.1 to 10.6 GHz. The overall size of designed antenna is 27 × 27 × 1.6 mm3 which comprises of novel structure of radiating patch and 50Ω CPW feed. After modification the final geometry of radiating patch, proposed antenna divulges the VSWR bandwidth of 11.88 GHz (2.12–14.0 GHz). Further, by introducing different types of slots in the final structure of radiating patch antenna exhibits Wi-MAX (3.16–3.76 GHz), WLAN (5.26–5.87 GHz) and X-band satellite communication (7.30–7.68 GHz) rejected bands. Furthermore, designed UWB antenna embellishes the gain of −7.64 dBi, −4.80 dBi and −4.92 dBi at rejected bands, whereas, the gain of antenna at other frequencies varies between 3.65 and 8.19 dBi. Proposed UWB antenna exemplifies the radiation efficiency variation in 77–98% except notched frequency bands. The radiation pattern and group delay of antenna is also at the acceptable level for existing UWB applications. Lastly, final optimized geometry of antenna with three band notched characteristics is being fabricated and verified for the validation of simulated results. Both the results are related and are found in good agreement with each other and also divulged that proposed antenna is eligible candidate for UWB applications with band rejection characteristics. [ABSTRACT FROM AUTHOR]

WRaINfo is a software for real-time weather radar data processing developed by the Helmholtz Innovation Lab FERN.Lab, a technology and innovation platform of the German Research Centre for Geosciences Potsdam (GFZ). WRaINfo is specifically designed for processing X-band weather radar data of FURUNO devices. The modules of the package allow to read and process raw data of the WR2120 and WR2100. For this purpose, many functions of the library wradlib are used and adapted. The processing is controlled by a configuration file, main functionalities include formatting, attenuation correction, clutter detection, georeferencing and gridding of the data. This allows the construction of reproducible, automatic data processing chains. The package is written in the Python programming language. The source code is publicly available on GitLab. Compiled versions are also available on PyPi. The package is distributed under the Apache 2.0 license. [ABSTRACT FROM AUTHOR]

The possibility has been explored to control the photonic Tamm resonances (TRs) in the one-dimensional microwave photonic crystal (MPC) with the dielectric filling by changing the thickness of the MPC’s outer layer adjacent to the heavily doped layer of the semiconductor GaAs structure. The controlled photonic TRs have been used to measure the conductivity of the heavily doped semiconductor layer. It has been shown that depending on the conductivity of the layer the specific tuning of the TR frequency is necessary in order to achieve a high sensitivity of the TR to the change of the conductivity. The possibility of observing the plasma resonance in the infrared range has additionally allowed to determine the concentration and mobility of free charge carriers in the heavily doped layer of the GaAs structure.

Bu makalede, X-Bant ’ta hibrit Mikroşerit-YTED (Yalıtkan Taban Entegreli Dalga Kılavuzu) bant geçiren filtrenin optimizasyon çalışması yapılmıştır. Yüksek geçiren bir YTED filtre ile alçak geçiren bir mikroşerit filtrenin seri entegrasyonuyla elde edilen hibrit bant geçiren filtrenin geometrisindeki asimetrik bölümler düzeltilmiştir. Optimizasyon çalışmasında, CST (Computer Simulation Technology) Studio Suite simülasyon programındaki 5 farklı optimizasyon algoritma tekniği hibrit M-YTED bant geçiren filtreye uygulanmıştır. Filtreye uygulanan bu tekniklerin sonuçları karşılaştırılmalı olarak verilmiştir. Metotlar karşılaştırıldığında, geçiş bandındaki S11 değerleri toplamının en düşük değerde olması nedeniyle Parçacık Sürü Optimizasyon Algoritması seçilmiştir. Filtrenin w4 parametresinin değeri 6,165 mm olarak elde edilmiştir. Filtrenin kalite faktörü, optimizasyon çalışmasıyla Guvenli ve diğ., (2021)’nin çalışmasına göre 3,21 kat artırılmıştır. Hibrit Mikroşerit-YTED bant geçiren filtrenin geçiş bandı [ω1-ω2] 7,60 GHz ile 8,40 GHz frekans aralığında, filtrenin merkez frekansı (ω0) 7,90 GHz, filtrenin bant genişliği de 0,80 GHz (%10,01) olacak şekilde tasarlanmıştır. M-YTED bant geçiren filtrenin simülasyon sonuçlarına göre, merkez frekansı 8,15 GHz ve bant genişliği 0,92 GHz'dir (%11,29). Analitik ve simülasyon sonuçları karşılaştırıldığında, analitik sonuçlara göre simülasyon merkez frekansındaki frekans değişimi %1,98 ve bant genişliği değişimi %15’dir. Analitik ve simülasyon sonuçlarının birbiriyle uyumlu olduğu görülmektedir.

This paper presents a quad-port multiple-input multiple-output (MIMO) single cylindrical dielectric resonator antenna (CDRA) for X-band applications. This approach is mainly based on selecting the proper feeding structure for each port as well as implanting vertical metallic vias (VMVs) to diminish the mutual coupling over a wide bandwidth. Two orthogonal apertures and two vertical probes are utilized as feeding structures to realize good isolation between all port combinations. For coupling mitigation between port1 and port2 that is due to the field distribution of the excited modes at these ports, four VMVs are inserted between them in appropriate positions to produce field orthogonality along wide bandwidth. The excited modes inside the proposed CDRA are H E 52 δ + 2 x , H E 52 δ + 2 y , HE 32δ + 2 , and TM 12δ + 2. Isolation better than -15 dB is attained across the overlapping band of 340 MHz (4 %); from 8.2 to 8.54 GHz. Moreover, the proposed DRA provides a gain of 5.17, 7.21, 7.77, and 7.78 dBi for the four ports at 8.45 GHz and the total efficiencies at all ports are from 65 to 85 % across the operating band. The MIMO performance of the proposed design shows a good envelope correlation coefficient (ECC), diversity gain (DG), total active reflection coefficient (TARC), channel capacity loss (CCL) and mean effective gain (MEG) through the whole band for all ports. [ABSTRACT FROM AUTHOR]

Microstrip patch antennas (MPAs) are essential components in modern wireless communication systems, and their design is significantly influenced by the properties of the materials used. In this study, we investigate the impact of incorporating composites of fumed silica within RT-Duroid dielectric material on the performance of microstrip patch antennas. The effective permittivity of the composite is calculated using the Maxwell-Garnett model. Through systematic theoretical studies, we analyze the performance of composite antennas with varying composite volumes and dielectric substrate thicknesses. Utilizing HFSS 13.0 software, we optimize the substrate thickness and antenna dimensions to design MPAs resonating at 10 GHz. The proposed antenna, with dimensions of 11.85 mm by 9.044 mm for the patch and 50 mm by 50 mm for the substrate, exhibits superior performance compared to conventional antennas, achieving a higher gain of 10 dB, good efficiency of 96 % along with favorable return loss characteristics. The frequency ranges of the C and X bands are better suited for military applications, weather radar, satellite communication, air traffic control, maritime radar, and remote sensing. This research underscores the significance of incorporating composite materials into MPA design to enhance performance and broaden application potential in modern communication technologies. • This study does a detailed analysis to determine how substrate thicknesses and VFs impact design using the MGM. • The proposed antenna achieves a remarkable 96 % efficiency, a gain of 10 dB, favorable return loss, and a dual-band nature. • A composite antenna operates in both the C and X bands with high gain, while a conventional antenna works in the X band. • These frequency bands are used for weather radar, marine radar, air traffic control, military, and remote sensing. • This analysis validates how composite substrates achieve a breakthrough in communication, where the materials can't. [ABSTRACT FROM AUTHOR]

Precise knowledge of the antenna pointing direction is a key facet to ensure the accuracy of observations from scanning weather radars. The sun is an often-used reference point to aid accurate alignment of weather radar systems and is particularly useful when observed as interference during normal scanning operations. In this study, we combine two online solar interference approaches to determine the pointing accuracy of an X-band mobile weather radar system deployed for 26 months in northern England (54.517°N, 3.615°W). During the deployment, several shifts in the tilt of the radar system are diagnosed between site visits. One extended period of time (>11 months) is shown to have a changing tilt that is independent of human intervention. To verify the corrections derived from this combined approach, quantitative precipitation estimates (QPEs) from the radar system are compared to surface observations: an approach that takes advantage of the variations in the magnitude of partial beam blockage corrections required due to tilting of the radar system close to mountainous terrain. The observed improvements in QPE performance after correction support the use of the derived tilt corrections for further applications using the corrected dataset. Finally, recommendations for future deployments are made, with particular focus on higher latitudes where solar interference spikes show more seasonality than those at mid-latitudes.

WRaINfo is a software for real-time weather radar data processing developed by the Helmholtz Innovation Lab FERN.Lab, a technology and innovation platform of the German Research Centre for Geosciences Potsdam (GFZ). WRaINfo is specifically designed for processing X-band weather radar data of FURUNO devices. The modules of the package allow to read and process raw data of the WR2120 and WR2100. For this purpose, many functions of the library wradlib are used and adapted. The processing is controlled by a configuration file, main functionalities include formatting, attenuation correction, clutter detection, georeferencing and gridding of the data. This allows the construction of reproducible, automatic data processing chains. The package is written in the Python programming language. The source code is publicly available on GitLab. Compiled versions are also available on PyPi. The package is distributed under the Apache 2.0 license.

In this paper, we propose a one-dimensional (1D) array antenna with improved sidelobe level (SLL) and cross-polarization (x-pol) characteristics. The array elements constituting the 1D array antenna comprise different numbers of dipole elements, and each array element has a different gain and E-field phase. The positions of the array elements in the z-axis direction are adjusted to equalize their E-field phases in the far field, and the array elements are arranged symmetrically with respect to the z-axis to obtain a low x-pol. The same amount of power is supplied to all the array elements of the 1D array antenna of the proposed structure. Therefore, a complexly structured feeding network is not required to achieve a low SLL and low x-pol. The gain of the proposed array antenna with a corporate feeding network is 15.2 dBi, and its SLL and x-pol level are–21.3 dB and 20.3 dB, respectively. The–10 dB impedance bandwidth of the proposed array antenna is 35.6% (8.3–11.9 GHz).

A metasurface (MS) based on loop elements operating in the near field of a linearly-polarized microstrip antenna is employed to realize a circularly polarized radiated field. The properties of the loop unit cell are highlighted with the help of the Characteristic Mode Analysis that is employed for investigating the achievable linear to circular polarization conversion bandwidth and providing the guidelines for the design of the final antenna. A finite structure comprising $4\times 4$ unit cells is tailored for achieving a circularly polarized far field within the whole X-band adopted for satellite communications (7.25 GHz-7.75 GHz, 7.9 GHz-8.4 GHz). A simple but effective single-port excitation scheme is adopted, and the overall performance are assessed by measurements on the fabricated prototype. The good agreement between simulated and measured results confirms the reliability of the proposed approach as well as the meaningful insight provided by Characteristic Modes Theory.

An X-band H-plane groove gap waveguide magic-T is presented as a combination of an H-plane and an E-plane T-junction. Two architectures can be derived by orientating the sum and difference ports to the same or opposite directions, respectively. Slot coupling allows the reduction of the device dimensions along the E-plane, and such a low profile can be attractive in all groove gap waveguide applications where compactness is required. A proof-of-concept prototype is fabricated with standard low-cost CNC milling machine manufacturing techniques. Good agreement between simulations and measurements is observed. [ABSTRACT FROM AUTHOR]

This article begins with an explanation of a frequency selective surface, also known as an FSS, which is used to increase gain across a wide frequency range. The proposed unit design is a modified combination of circular and square elements with two cross dipoles and a T-type structure at the inner side. In the second step of the process, a single wideband antenna that covers the same range as FSS is designed and then analyzed in terms of its gain and radiation patterns. After that, an antenna array was built using the same solo structure in order to take advantage of the benefits that come with using an array system. The array is made up of elements that are CPW fed. A ground-backed T-shaped power divider network with additional shorting pins is used to supply power to the entire array. In the fourth step, an array of the FSS unit cell has been positioned beneath the UWB solo antenna and its array in order to investigate the possibility of improved gain and radiation pattern. The FSS equivalent lumped circuit model is presented here for validation purposes. It has been determined that the results of the experiment and the simulation are consistent with one another. In contrast to the structures that have been reported in the past, the newly developed model possesses a greater bandwidth, a higher gain, and a lower profile. [ABSTRACT FROM AUTHOR]

Design and fabrication of an effective, affordable, and lightweight material to solve the electromagnetic interference (EMI) problem, through improving the microwave absorption, have become an urgent need during the present period of fast growth of electronic devices and wireless telecommunication technology. Manganese ferrite MnFe2O4 nanoparticles (MFO NPs) with three different particle sizes were synthesized using the hydrothermal reaction technique. The MFO NPs were then mixed with carbon nanotubes (CNTs) to fabricate a new EMI shielding mat, through a free polymer-binder surface-engineered tape-casting (SETC) method. The fabricated CNTs-MFO mats have demonstrated superior EMI shielding in the X-band. CNT-only mat (with 48 µm thickness) had a total effective shielding (SEAll), absorption shielding (SEA), and reflection shielding (SER) of 36 dB, 23 dB, and 10 dB, respectively. SEAll of 36 dB proves that the CNT-only mat is a promising material for microwave absorbing materials. However, 1 wt.% of CNTs-MFO-1 has enhanced the SEAll by 14.5% at a frequency of 10.51 GHz. This improvement in SEAll is because of the MFO's magnetic properties and the heterogeneous structure created by the MFO within the CNT mat, which enhances the EM wave's absorption. [ABSTRACT FROM AUTHOR]

A compact 15 mm × 15 mm multi-band metamaterial-inspiredprinted antenna, composed of a simple microstrip antenna and a metamaterial superstate, is developed to accommodate nowadays advanced wireless communication devices and networks, where multi-functional tasks are simultaneously performed in different frequency ranges efficiently. A quintuple homocentric circular split ring resonator is explicitly designed as a band enhancer metamaterial superstate. The metamaterial geometry and orientation associated with the antenna location and radiating are optimized for the greatest consequence, where the resonances electrically and magnetically couple with the antenna radiation, generating quintuple bands in the X band: 8–12 GHz. The main lobe directions indicate an excellent directional propagation. This metamaterial-inspired antenna was designed and fabricated using a low cost commercial FR4 substrate offering a good cost margin for potential mass production. Four of five bands have a gain greater than 6dBi, which can be improved by using low-loss substrate. The measured and simulated results are in good agreement. [ABSTRACT FROM AUTHOR]

A compact and triple-band polarization converting reflective type metasurface (PCRM) with a high polarization conversion ratio (PCR) is proposed for strategic wireless antenna-integrated applications. The unit cell of the metasurface is composed of S- and G-shaped patches separated with a parasitic gap and the grounded via is connected to the full ground plane. The unit cell is etched on an FR4 substrate (dielectric constant, εr = 4.4, loss tangent, tan δ = 0.02), with compact dimensions of 10 mm3 × 10 mm3 × 1.6 mm3. This structure provides a resonance at 5.2 (ISM), 6.9, and 8.05 GHz (X-band) frequencies. The designed unit cell structure is studied for Transverse Electric (TE)/Transverse Magnetic (TM) incident waves and their responses to the various incident angles. The corresponding PCR is calculated, which shows 92% in the lower frequency band (5.2 GHz), 93% in the second frequency band (6.9 GHz), and 94% in the high-frequency band (8.05 GHz). The total efficiency of the structure shows 83.2%, 62.95%, and 64.6% at the respective resonance bands. A prototype of the proposed PCRM with 3 × 3 unit cells is fabricated to validate the simulated results. The experimental data agrees with the simulation results. The compactness, triple-band operation with a high PCR value of more than 92% makes use of the designed metasurface in wireless antenna-integrated applications at ISM and X-bands. [ABSTRACT FROM AUTHOR]

In this paper, two different bands operated on the body antenna are presented with a very small dimension of 22 × 26 × 1.6 mm3. The ground plane is modified and loaded with rectangular slots for getting the desired operating bands and for better matching. The proposed antenna is fabricated on FR-4 dielectric material, and it is operatable for WiMAX (3.3–3.6 GHz) as well as for X-band (8–12 GHz) with bandwidth efficiency of 41.8% and 40% respectively. The proposed antenna is successfully implemented on the body phantom justifying the optimal values of SAR for both operating bands of frequencies. The monopole antenna can be operated for different broadband communicational applications, satellite communication, and military operations. [ABSTRACT FROM AUTHOR]

An inset fed-microstrip patch antenna (MPA) with a partial ground structure is constructed and evaluated in this paper. This article covers how to evaluate the performance of the designed antenna by using a combination of simulation, measurement, creation of the RLC equivalent circuit model, and the implementation of machine learning approaches. The MPA's measured frequency range is 7.9–14.6 GHz, while its simulated frequency range is 8.35–14.25 GHz in CST microwave studio (CST MWS) 2018. The measured and simulated bandwidths are 6.7 GHz and 5.9 GHz, respectively. The antenna substrate is composed of FR-4 Epoxy, which has a dielectric constant of 4.4 and a loss tangent of 0.02. The equivalent model of the proposed MPA is developed by using an advanced design system (ADS) to compare the resonance frequencies obtained by using CST. In addition, the measured return loss of the prototype is compared with the simulated return loss observed by using CST and ADS. At the end, 86 data samples are gathered through the simulation by using CST MWS, and seven machine learning (ML) approaches, such as convolutional neural network (CNN), linear regression (LR), random forest regression (RFR), decision tree regression (DTR), lasso regression, ridge regression, and extreme gradient boosting (XGB) regression, are applied to estimate the resonant frequency of the patch antenna. The performance of the seven ML models is evaluated based on mean square error (MSE), mean absolute error (MAE), root mean square error (RMSE), and variance score. Among the seven ML models, the prediction result of DTR (MSE = 0.71%, MAE = 5.63%, RMSE = 8.42%, and var score = 99.68%) is superior to other ML models. In conclusion, the proposed antenna is a strong contender for operating at the entire X-band and lower portion of the Ku-band frequencies, as evidenced by the simulation results through CST and ADS, it measured and predicted results using machine learning approaches. [ABSTRACT FROM AUTHOR]

Silicon carbide (SiC) has good chemical resistance, excellent mechanical properties, thermal conductivity, especially in extreme conditions of application, and has proved to be a very promising electromagnetic absorption material. However, single silicon carbide cannot meet the increasing demand for high performance of absorbing materials. It has become an important research direction to combine it with other absorbing materials to improve its absorbing performance. In this study, a composite absorber material was prepared by 50 wt.% micron-sized beta-silicon carbide (β-sic) powder, mixed with a 0.2 wt.% multiwalled carbon nanotubes (MWCNTs) and 50 wt.% polyurethane (PU) substrate. The mixture was stirred and deaerated to form a slurry, and sprayed onto synthetic fabric. The results showed that the composite material was flexible, with a thickness of less than 2 mm and favorable adhesion. The results obtained by reflection graph of the radar waves, indicated that the return loss within the X-band range (8–12 GHz) was less than −40 dB, indicating favorable radar wave absorption. Therefore, composite materials could thus be used successfully as radar wave absorbers, and was suitable for stealth materials in "asymmetric warfare". [ABSTRACT FROM AUTHOR]

This article presents broadband balanced low‐noise amplifier (LNA) operating at X‐band, which uses composite right/left‐handed (CRLH) transmission lines as input–output matching networks. Proposed LNA eliminates lumped DC‐blocking capacitors and is combined with a hybrid coupler to achieve better stability and matching. Presented CRLH matching technique enhances the matching quality, reduces the overall size and considerably improves the bandwidth and noise performance. The matrix analysis of the CRLH structure is provided to determine the exact dimension of microstrip lines for the highest stable gain and the lowest noise figure (NF). The LNA structure uses a HJFET technology as an active device, which is simulated using an ADS momentum and small‐signal scattering parameters provided by the manufacturer. This LNA offers an improved impedance matching and measured the 20 dB S11 band‐width of 16% (8.3–9.7GHz), which is in good agreement with simulation. Total area occupied by the fabricated LNA is only 1.7λ0×0.9λ0@ 8.3GHz. The LNA also provides <1.8 dB NF based on the IEEE standard temperature (16.85 Celsius), and 1 dB gain flatness throughout the entire band along with a 1 dB compression point of −1 dBm and an output third point intercept point of 19.5 dBm. The proposed CRLH‐based LNA can be a good candidate for compact receivers and sensors. [ABSTRACT FROM AUTHOR]

Dielectric properties of nanosized Lithium Orthosilicate (Li4SiO4) and linear low-density polyethylene composite at X-Band frequencies are investigated, to realize its utility as a substrate for microwave devices. Solid state technique is used to synthesize nano Li4SiO4. To confirm the structural and morphological properties of the synthesized nano Li4SiO4, X-ray diffraction, Fourier transformed infrared spectroscopy and transmission electron microscopy are used. Composites of nano Li4SiO4 and linear low-density polyethylene matrix are synthesized with varying weight fraction of nano Li4SiO4 viz. 2%, 4% and 6%. The lateral portion of a fractured sample (composite) is examined using scanning electron microscope to confirm homogeneous dispersion of nano Li4SiO4 in linear low-density polyethylene matrix. Water absorption measurement of all the composites are carried out based on ASTM D570-98. Densities of the composites are measured via hydrostatic weighing by using Archimedes principle. Complex permittivity and permeability measurement of the composites are recorded by utilizing Nicholson-Ross approach. For all weight fraction of the nano inclusions, the real component of permittivity and dielectric loss tangent of the composites in the X-band are found to be in the range of 2.2 - 2.6 and 10-2 -10-4, respectively. Return losses for the composites are calculated from complex permittivity and permeability values to validate its applicability as substrate for various high frequency applications. [ABSTRACT FROM AUTHOR]

In this letter, a novel wideband microstrip to additively fabricated waveguide transition is presented. The proposed design takes advantage of the flexibility of 3-D printing to realize a highly integrated transition from the microstrip line on a printed circuit board (PCB) to an air-filled waveguide using an additively manufactured radiating probe. The idea is experimentally verified by the realization of an exemplary transition working within the X-band at $f_{0} =10.5$ GHz. The measured performance of the back-to-back transition proves its usefulness and possibility of utilization in highly integrated PCB-waveguide circuits. A PolyJet printing technology with copper electroplating was used in combination with PCB on microwave grade laminate. A bandwidth of $f_{H}/f_{L} =1.8$ was obtained with the impedance match better than 9.5 dB and in-band insertion loss per transition below 1.1 dB. [ABSTRACT FROM AUTHOR]

Abstract In this paper, a broad band A-sandwich radome wall structure based on band-pass FSS (frequency selective surface) is proposed for an airborne radar applications. The FSS structure having two square conducting rings, which are embedded on either side of core layer. The conventional and proposed FSS based radome wall is analyzed with different incidence angles (0°, 10°, 20° and 30°) for both TE and TM polarization. The radome wall structure consist of a low density Nomex honeycomb core layer sandwiched between two high density Quartz skin layers. The structure shows the percentage impedance bandwidth of 40.8 % in the frequency range from 7.8GHz to 11.8GHz with sharp roll-off characteristics. The proposed novel approach involves high frequency unit cell simulation, which is carried out using EM Simulation Tool. To understand the practical behavior of the proposed structure for radome application the conformal analysis has been also carried out, with respect to different radius. The superior EM performance of the proposed broadband novel radome wall structure makes it suitable for the design of airborne radome.

Amorphous polymer-derived Si(Al)CNO ceramics with different Al contents were successfully prepared using polyvinylsilazane (PVSZ) doped with different mass fractions (0 to 15 wt%) of aluminum tri-sec-butoxide (ASB) as the precursors. The thermogravimetric, crystal morphology, microstructure, electrical conductivity and dielectric properties of Si(Al)CNO ceramics were characterized and tested, respectively. The results show that the porosity of Si(Al)CNO ceramics first decreased and then increased with the increase of ASB doping content. The electrical conductivity of SiAlCNO-5, SiAlCNO-10 and SiAlCNO-15 ceramics gradually decreased from 2.80 × 10-9 to 0.89 × 10-9 (Ω cm)-1. Their conductivity was related to free carbon in the ceramics based on Raman spectroscopy. The average permittivity of SiCNO, SiAlCNO-5, SiAlCNO-10 and SiAlCNO-15 ceramics gradually increased from 3.63 to 3.93 with the increase of ASB doping content in X-band. The dielectric loss of SiAlCNO ceramics doped with ASB was smaller than that of SiCNO ceramics. But with the continuous increase of ASB doping content, the dielectric loss of SiAlCNO ceramics also increased. The permittivity and dielectric loss of Si(Al)CNO ceramics were related to their porosity and electrical conductivity. The average absorption coefficient of Si(Al)CNO ceramics were less than 0.020, while their transmission coefficient were greater than 0.500. It was found that the amorphous Si(Al)CNO ceramics exhibit good electromagnetic wave transmission properties. [ABSTRACT FROM AUTHOR]

This article provides a 4-elements planar array of fractal patch antennas for X-band wireless communication, especially amateur-radio (10.00–10.50 GHz) applications. The single constituent of the indicated array is a freshly designed hybrid-fractal antenna with a modest gain and low cross-pol. level along the primary beam's path. The exhibited hybrid-fractal design was created using the Minkowski 1 s t iteration, followed by a 50 % scaling to a square geometry in the next stride. The compact planar array structure incorporates the Wilkinson power divider-based corporate feed network. The solo antenna built resonates at 10.02 GHz and offers 10.67 dBi of massive gain and 0.395 GHz of return-loss bandwidth, respectively. At 10.05 GHz resonating frequency, the array prototype gives 16.54 dBi absolute gain and 0.318 GHz impedance bandwidth. Printed prototypes achieved radiation efficiency of 96 % and 86 % , respectively. Both prototypes had computed aperture efficiency of 73 % and 76 % , respectively. There is a great deal of agreement between the prototypes' measured and simulated findings. [ABSTRACT FROM AUTHOR]

Transmitarray is a high gain antenna suitable for various applications such as satellite communications, automotive radars, and future cellular communication systems. In order to attain a high gain, the diverging rays are focused by compensating the phase of the rays. The unit cell elements in the transmitarray are responsible for passing the electromagnetic energy appropriately to compensate for the phase excesses. A transmitarray antenna with 7×7 elements was designed and realized at a frequency of 9.8 GHz. The unit cell element consists of two coupled open rectangular resonator loops to sharpen the transmission stop region, broadening the phase range compared to a single open rectangular resonator loop. The fabrication process uses the Rogers Duroid 4003C substrate. A gap of 4 mm separates the substrate layers. The antenna has a gain of 18.5 dBi and an aperture efficiency of 31.7%. [ABSTRACT FROM AUTHOR]

This study aims at relating the stickiness parameter ($\tau$) of the dense media radiative transfer theory in quasi-crystalline approximation of Mie scattering of densely packed sticky spheres (DMRT-QMS), to the physical parameters of the layered snowpack. A relationship has been derived to express $\tau $ , which modulates the attractive contact force between ice spheres, as a function of ice volume fraction ($\phi $) and coordination number ($n_{c}$). Since $\tau $ is not a measurable parameter, this is a step forward with respect to what is commonly made in the literature, where $\tau $ is assumed as an arbitrary parameter, generally ranging between 0.1 and 0.3, to fit simulated backscattering data with those measured. As a first validation, DMRT-QMS was integrated with the SNOWPACK model to simulate backscattering at X-band (9.6 GHz) driven by nivo-meteorological data acquired on a test area located in Monti Alti di Ornella, Italy. The simulations were compared with Synthetic Aperture Radar COSMO-SkyMed (CSK) satellite observations. The results show a significant agreement ($R^{2} =0.68$), although for a limited dataset of eight points in a unique winter season. [ABSTRACT FROM AUTHOR]