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A printed monopole super wideband (SWB) antenna is presented in this paper. It consists of a beveled-shaped radiator and a tapered ground plane. It is investigated that tapering of the radiator and ground plane enhances the impedance matching and results in broad impedance bandwidth. The experimental result depicts that the antenna achieved 164.9% impedance bandwidth from 2.6 to 27.27 GHz. Furthermore, to prevent the interference caused by communication systems within the ultra-wideband (UWB) range, dual-band rejection at Wi-MAX (2.7–4 GHz). and X-band (8.5–12 GHz) are introduced by etching an H-shape and two back-to-back C-shaped notches in the radiator and feedline, respectively. The measured result demonstrates that both slots effectively reject the desired frequency bands with a small shift in the lower frequency edge from 2.41 to 2.6 GHz. In addition, the proposed antenna application is shown in the two elements MIMO system where a bowtie decoupling structure is utilized to improve the isolation. It is found that the presence of a decoupling structure improves the isolation by up to 60%. To characterize the diversity performance, parameters such as Diversity Gain (DG), Envelop Correlation Coefficient (ECC), Channel Capacity Loss (CCL), and Mean Effective Gain (MEG) are calculated and all are found in the acceptable limit. [ABSTRACT FROM AUTHOR]

In this work, a quad-port fractal MIMO antenna is configured, simulated, and experimented for ultra-wideband performance with the elimination of three interfering narrow bands. The antenna is assembled on dual 80 × 99.4mm2 FR-4 dielectric substrates wherein the top substrate comprises four 2nd iterative Sierpinski gasket fractal patches and the bottom substrate incorporates a feeding arrangement. The aperture-coupled feeding approach is employed to activate the fractal radiators. The multi-frequency response produced by fractal antenna elements is transformed into a wide working range by modifying apertures (clipped from the ground surface) into spiral-shaped structures and offsetting the feedlines toward the right. The designed array effectively radiates in the 3.07–11 GHz range with 112.7% fractional bandwidth while maintaining minimal inter-element isolation of 16.19 dB. Additionally, each feedline is amalgamated with circular split-ring resonators, U-slots, and rectangular split-ring resonators to eradicate the interference emerging from the C-band (downlink satellite), WLAN, and radio-location band, respectively. Several diversity operation attributes are analyzed and are found to inhere to their admissible standards. The measured performance of the fabricated antenna design (with and without band-stop structures) depicts an agreeable similitude with the simulation results, thus validating the real-world operability of the proposed MIMO antenna in ultra-wideband communication devices. [ABSTRACT FROM AUTHOR]

Time-Sensitive Networking (TSN) requires clock synchronization superior to the well-known Network Time Protocol (NTP). The IEEE 802.1AS-2020 used for synchronization in TSN networks is based on the IEEE 1588-2019 standard (also known as Precision Time Protocol, PTP) defines methods and tools to perform sub-microsecond time synchronization over vari- ous communication channels. However, the IEEE 1588 implementation is commonly used with wired communication protocols, although there are use cases that could gain an advantage from a wireless solution. This paper investigates the possibility of PTP clock synchronization through wireless Ultra Wideband (UWB) communication. UWB excels where other wireless technologies are lacking: it provides high accuracy timestamping even if multipath propagation is present. The method is evaluated using commercial, well-accessible cheap hardware, resulting in the order of 10-nanosecond accuracy. The paper also highlights the main error components and requirements for improving wireless PTP synchronization. [ABSTRACT FROM AUTHOR]

In this paper, a novel ultra-wideband UWB antenna element with triple-band notches is proposed. The proposed UWB radiator element operates from 2.03 GHz up to 15.04 GHz with triple rejected bands at the WiMAX band (3.28–3.8 GHz), WLAN band (5.05–5.9 GHz), and X-band (7.78–8.51 GHz). In addition, the radiator supports the Bluetooth band (2.4–2.483 GHz). Three different techniques were utilized to obtain the triple-band notches. An alpha-shaped coupled line with a stub-loaded resonator (SLR) band stop filter was inserted along the main feeding line before the radiator to obtain a WiMAX band notch characteristic. Two identical U-shaped slots were etched on the proposed UWB radiator to achieve WLAN band notch characteristics with a very high degree of selectivity. Two identical metallic frames of an octagon-shaped electromagnetic band gap structure (EBG) were placed along the main feeding line to achieve the notch characteristic with X-band satellite communication with high sharpness edges. A novel UWB multiple-input multiple-output (MIMO) radiator is proposed. The proposed UWB-MIMO radiator was fabricated on FR-4 substrate material and measured. The isolation between every two adjacent ports was below −20 dB over the FCC-UWB spectrum and the Bluetooth band for the four MIMO antennas. The envelope correlation coefficient (ECC) between the proposed antennas in MIMO does not exceed 0.05. The diversity gains (DG) for all the radiators are greater than 9.98 dB. [ABSTRACT FROM AUTHOR]

A compact, four-element planar MIMO (Multiple Input, Multiple Output) antenna that operates in an ultra-wideband is presented for diversity application. The orthogonal position of the unit cells replicates the single antenna thrice, thereby decreasing mutual coupling. A UWB MIMO antenna measuring 35 × 35 × 1.6 mm3 is built using a microstrip line (50 Ω impedance) on an FR4 substrate having a thickness of 1.6 mm. The ground plane and radiator of this antenna are adjusted in several ways to bring it within its operating constraints between the frequencies of 3.1 GHz and 10.6 GHz. This technique makes the antenna small and covers the entire ultra-wideband (UWB) frequency range. The NI USRP was used to test the proposed MIMO antenna to determine its real-time performance. Based on the computed results, we conclude that this proposed antenna has outstanding characteristics in terms of performance and is suitable for wireless ultra-wideband indoor communication and diversity utilization with a small size. [ABSTRACT FROM AUTHOR]

In this manuscript, a compact (size only 9.8mm*9.8mm) Ultra Wide Band (UWB) bandpass filter with a new structure is proposed, which can be used in the UWB wireless communication band authorized by the FCC. The top plane is composed of a pair of back-to-back microstrip lines, and the ground plane structure is based on an asymmetric coplanar waveguide-defect ground structure (ACPW-DGS). UWB is formed by the vertical electromagnetic coupling of the top plane and the ground plane. On this basis, split ring resonator (SRR) and C type resonator (CTR) are utilized to place double notch bands. A novel third order nested C-type resonator (TONCTR) is obtained by performing CTR, which can further optimize the upper stopband while ensuring double notch bands. The filter can be used for filtering within the UWB system, and it can also avoid the amateur radio band (9.2 -10.3GHz) and the X-band satellite link band (9.6-12.3GHz) on UWB communication systems. Finally, the measured results from the fabricated prototype are basically consistent with the simulation results. [ABSTRACT FROM AUTHOR]

In this letter, a 4.5–7.5 GHz highly integrated transceiver front‐end, incorporating two single‐pole three‐throw (SP3T) transmit/receive (T/R) switches, a low‐noise amplifier (LNA), a power amplifier (PA), and a bypass path for UWB positioning and communication systems applications, is reported. The mode switches among transmitting, receiving, and bypass are achieved by utilizing two control voltages through integrating a 2–4 decoder. Meanwhile, to ensure low‐power dissipation in different modes, the LNA and PA work in different modes (enable or disable) for transmitting and receiving status while both the LNA and PA are disabled for bypass mode. Fabricated by using 0.5‐μm GaAs pHEMT process, the presented FEM achieves 20‐dB gain, and 2.5‐dB typical noise figure for receiving mode, 8‐dB gain, and 16‐dBm OP1dB for transmitting mode, and 1.8 dB insertion loss for bypass mode, with a compact chip area of 1.5 mm × 1.7 mm. To the best of authors' knowledge, the presented circuits are the highest integrated and smallest chip area transceiver front‐end for UWB application among all previously reported UWB‐related RF front‐end chips. [ABSTRACT FROM AUTHOR]

This paper proposes the step-by-step design procedure for obtaining independent dual band-notch performance, which provides a valuable method for designing tunable dual band-notched UWB antenna. The proposed antenna consists of the semicircle ring-like radiating patch with an elliptical-shaped slot and double split ring resonators on the top surface of the substrate and defected ground structure (DGS) on the bottom surface of the substrate. The operating frequencies ranged from 1.3 to 11.6 GHz (S11 < − 10 dB). By loading varactor diodes at the gap of the resonators structure and changing the varactor diode's reverse bias voltage(0–30 V), a wider band-notched tuning range from 2.47–4.19 to 4.32–5.96 GHz can be achieved, which covers the whole WiMAX band and WLAN band. The experimental results agree well with the simulated results. The notched gain at notched frequency points is about − 5.3 dBi and − 5 dBi, demonstrating that the narrow-band interference signal could be efficiently suppressed. The security of UWB communication systems can be further enhanced. Meanwhile, the selection of varactor diode and DC bias circuit are fully considered. Hence, the accuracy of the experiment results and antenna operating performance have been improved. Furthermore, the proposed antenna only has an electrical size of 0.26λ*0.19λ at 1.3 GHz. Compared to the related reported antennas, the proposed antenna has achieved a simpler structure, low profile, compact size, tunable dual band-notched characteristics, extensive independent tunable range, and good band-notched performance simultaneously, to the best of our knowledge. The proposed antenna is believed to have a valuable prospect in UWB communication, Wireless Body Area Network, Industry Science Medicine, mobile communication applications, etc. [ABSTRACT FROM AUTHOR]

A CPW‐fed double‐leaf‐shaped ultra‐wideband planar antenna, along with its four‐port MIMO configuration, is presented. The MIMO element is designed through combining the techniques of a modified radiator, coplanar waveguide feeding arrangement, and defected ground structure. The size and operating bandwidth of the MIMO element are 14 × 19 mm2 and 3.73 GHz to 22.01 GHz, respectively. The MIMO element has a peak realized gain of 4.27 dBi and has stable radiation patterns at lower frequencies. In the MIMO configuration, four replicas of this MIMO element are orthogonally arranged to ensure polarization diversity. A rotated plus‐shaped decoupling structure is integrated with the MIMO design for enhancing intra‐element isolation. The proposed MIMO design offers an ultra‐wide bandwidth of 18.28 GHz (3.73 GHz–22.01 GHz), an isolation value of more than 22 dB and an overall footprint of 40 × 40 mm2. ECC < 0.03, CCL < 0.35, MEG < −4 dB, and TARC < −20 dB have been achieved. The MIMO design is fabricated and experimentally tested. The measured data is found to agree well with the simulated data. This antenna will be highly suitable for many ultra‐wideband communication applications in today's world. [ABSTRACT FROM AUTHOR]

Localization is a keystone for a robot to work within its environment and with other robots. There have been many methods used to solve this problem. This paper deals with the use of beacon-based localization to answer the research question: Can ultra-wideband technology be used to effectively localize a robot with sensor fusion? This paper has developed an innovative solution for creating a sensor fusion platform that uses ultra-wideband communication as a localization method to allow an environment to be perceived and inspected in three dimensions from multiple perspectives simultaneously. A series of contributions have been presented, supported by an in-depth literature review regarding topics in this field of knowledge. The proposed method was then designed, built, and tested successfully in two different environments exceeding its required tolerances. The result of the testing and the ideas formulated throughout the paper were discussed and future work outlined on how to build upon this work in potential academic papers and projects. [ABSTRACT FROM AUTHOR]

In this paper, we propose a circularly polarized (CP) ultra-wideband (UWB) MIMO antenna. Compared with common linearly polarized (LP) UWB antenna, the proposed antenna can excite circular polarization (CP) mode for WLAN communication and its impedance bandwidth can also fully cover UWB spectrum. It consists of identical circularly polarized antennas. Each unit adopts circular monopole with extended orthogonal rectangle patch to realize broadband and symmetrical rectangular ground with slot in the diagonal of each antenna unit to achieve circular polarization for WLAN band. It has a very compact size and the dimension is 25 χ 51 χ 0.8 mm3. The impedance bandwidth of the proposed antenna is from 3.1 GHz to 13.5 GHz, with average gain of 4 dBi, fully covering UWB bandwidth and enhanced by 38%. At the same time, circular polarization is achieved by embedding two symmetrical rectangular slot structures in the two opposite corners of every antenna unit. The extended orthogonal rectangle patch is introduced to enhance impedance bandwidth and broaden axial ratio (AR) bandwidth. The measured 3 dB axial ratio (AR) bandwidth is 1.8 GHz (4.7-6.5 GHz), fully covering WLAN band. Meanwhile, the slit slot between antenna units and rectangular openings are introduced to achieve high isolation. The proposed antenna keeps ECC (envelope correlation coefficient) below 0.01, which showing good isolation and diversity characteristics. The proposed antenna can simultaneously operate in the UWB spectrum and exhibit circularly polarized (CP) radiation characteristic in WLAN. [ABSTRACT FROM AUTHOR]

In this paper a band notch characteristics reconfigurable UWB leaf shape monopole antenna is reported. The proposed antenna size is 42Ã--32Ã--1.6 mm³ and simulated S11 -10dB impedance bandwidth is from 2.1 to 13.0 GHz. The notch bands are embodied into the designed antenna to suppress Bluetooth and WiFi bands from 2.3-2.7 GHz and 4.6-5.3 GHz. The PIN Diode is loaded to slot on the DGS to achieve notch bands. It has 4.48dB and 1.7dB gain achieved when diode ON and OFF condition. Further, it encompasses a bio-inspired leaf shape patch having high feasibility for deployment in secret and military purposes. [ABSTRACT FROM AUTHOR]

Antennas are the building block of radiative hyperthermia (HT) applicators. This study proposes a compact UWB antenna specifically tailored to meet the requirements for deep HT array applicators. The proposed Open Ridged‐Waveguide (ORWG) antenna, which is an adaptation of a double‐ridged horn antenna, operates over the frequency band of 400–800 MHz. It was experimentally assessed as a single element. The quality metrics considered were reflection coefficient, penetration depth, effective field size (EFS), and mutual coupling. The design shows a 75.5% fractional bandwidth with a reflection coefficient measured to be below −10 dB from 367 up to 820 MHz. The EFS is greater than the physical dimensions of the 3‐by‐4 cm aperture. The mutual coupling between two adjacent elements in the array, measured in a flat phantom arrangement, is lower than −30 dB throughout the entire band. The antenna's performance was further tested in two deep HT scenarios in order to assess the mutual coupling and focussing abilities while in the array configuration. To this end, phased array applicators consisting of 10 and 16 ORWG antennas were simulated in CST, and the results are presented for a homogeneous cylindrical muscle phantom and a realistic patient model, respectively. The good agreement between the simulated and measured results suggests that the antenna can be successfully used for HT. [ABSTRACT FROM AUTHOR]

In this paper, an ultra‐wideband multiple‐input multiple‐output antenna with dual band‐notched characteristics is proposed. The radiating element is an octagonal structure using a tapered microstrip line to feed. A multimode resonator is introduced on one side of the microstrip feed line to achieve dual band‐notched characteristics, which eliminates the interference of wireless local area network band and X satellite communication frequency band. By using a diamond‐shaped defect ground structure and extending a parasitic branch at the centre axis of the ground, the mutual coupling of the antenna is reduced to −20 dB. The proposed antenna has a compact size of 30 × 35 × 0.8 mm3. The measured results are in good agreement with the simulation results. The proposed antenna covers 3.1–10.6 GHz with dual notched‐band characteristics and the mutual coupling below −20 dB. The antenna has a good diversity performance as the envelope correlation coefficient <0.03. The antenna is suitable for ultra‐wideband communications. [ABSTRACT FROM AUTHOR]

Summary: In this manuscript, a methodology of pulse shape modification is used for the directivity enhancement of ultra‐wideband (UWB) beam formation, to suppress the interference due to co‐existing narrowband communications with UWB signals. We propose that the modified pulse shaping produces more direct beam patterns for the tapped delay line antenna arrangements. These direct beam patterns are obtained for the smaller values of inter‐element spacing. This reduction of inter‐element spacing can provide more space for other development and compact the size of the any UWB antenna unit. [ABSTRACT FROM AUTHOR]

A novel magneto‐electric dipole antenna with dual linear polarization, ultra‐wideband, and good unidirectional radiation is proposed. It consists of two bowtie‐shaped electric dipoles, two orthogonally placed Γ‐shaped feeding structures, four parasitic patches, and a metal cylindrical cavity. In order to illustrate the operating mechanism, the radiation field is simulated and analyzed at lower, medium, and higher frequencies. Three operating modes (electric dipole mode, ME dipole mode, and magnetic dipole mode) are found and discussed to show the ultra‐wideband radiation. Especially, the ME dipole mode is analyzed in detail. By adding four parasitic metal patches, the boresight gain at the lower and higher bands is enhanced. At 1.75 and 5.6 GHz, the boresight gain improves 1.65 and 2.8 dB, respectively. Additionally, the height of the cylindrical cavity is also analyzed to show its effect on VSWR and boresight gain. Finally, a prototype is designed, fabricated, and measured. Measured results show that the impedance bandwidth for VSWR <2 is up to 92.3% (from 2.1 to 5.75 GHz) and 103% (from 1.8 to 5.65 GHz) at the two feeding ports, respectively. In its impedance bandwidth, the boresight gain is 8.75 ± 1.95 dBi and 8 ± 3.3 dBi at two ports, respectively. And, the radiation patterns in the operating band show a unidirectional radiation characteristic. Therefore, the proposed antenna can be a candidate in the future UWB communication system. [ABSTRACT FROM AUTHOR]

How to integrate the tightly coupled dipole array (TCDA) with tile‐based power combination network (PCN) has never been discussed in literatures. However, it is a critical issue should be resolved for TCDA's compact design. This article investigates a crucial front‐end component—8 × 8 dual‐polarized tightly coupled dipole subarray (TCDSA)—for ultra‐wideband satellite communication (SATCOM). A tile‐based network architecture is proposed to realize a low‐volume active PCN for the TCDSA. Then, a vertical interconnection module is proposed to totally eliminate coaxial cables between antenna elements and the PCN. A prototype of the TCDSA is developed. The PCN is elaborately integrated with the antenna elements in a compact space within a total thickness of 2.0 cm. The overall height of the prototype is 206.6 mm (2.07λH), where λH is the wavelength at the high‐end operating frequency. The fabricated dual‐polarized prototype demonstrates a decade bandwidth of 0.3–3.0 GHz with low cross‐polarization levels (<−30.0 dB). Because of the compact structure and excellent performance, the developed TCDSA will find applications in future receiving systems for SATCOM. [ABSTRACT FROM AUTHOR]

Unmanned aerial systems can widely be expected to realize the demand for “machine for man” in the field of precision agriculture. Particularly, the workforce is aging in most industrial countries, together with ever-increasing consumption, unreasonable exploitation of resources, and gradually deteriorated ecological environment. Correspondingly, these issues have posed a great challenge to sustainable agriculture in the future, as rapid information technology (IT) is emerging. Nevertheless, current farmland is distributed mainly on a small to medium scale after decades of land use regulation. By contrast, modern agricultural production requires a large scale, precision, and low cost in the direction of automation. Furthermore, most advanced technologies generally present relatively high cost, complex composition, and limited application, such as satellite, visual, and radar navigation. Therefore, it is highly necessary to explore a detection system with low-cost, high-precision, and easy-to-use navigation parameters. Fortunately, ultra-wideband communication (UWB) has received extensive attention in the field of wireless communication transmission in recent years. UWB-based positioning is one of the most promising high-precision technologies, providing convenience and new ideas for autonomous navigation in agriculture and industry. An important new initiative is also currently to vigorously promote land rectification and construction of high-standard farmland at this stage of agricultural production in China. This scheme has laid a solid foundation to realizing autonomous navigation for large-field agricultural machinery in the agronomic aspects. However, the current national large-field agriculture is still dominated by the individual management system and the family joint production contract responsibility system. Specifically, 90% of large-field agriculture is characterized by regional production on a small scale. Fragmented distribution is still the main body with a concentrated planting pattern of small fields at the 100-metre level, especially in the southern paddy fields. At present, there are two types of UWB positioning: short-range and long-range. The long-range module can reach more than 300m, up to 1,200m, and the optimal positioning accuracy can be known within 5cm. It indicates that the long-range UWB wireless range sensor can meet the demand for autonomous navigation and the driving of farm machinery in large fields in terms of range and detection accuracy. Furthermore, there is also local, moderately small-scale and scattered production, particularly on the large-field cultivation patterns in the southern paddy fields of China. The main factors are confined to the development of satellite, visual and radar navigation, including the high investment, complicated structure, limited applicable environment, and susceptibility to environmental interference. In this study, an improved signal angle of arrival (AOA) model was proposed to detect the navigation parameters under the reciprocal operation patterns of agricultural machinery in an unmanned environment in a large field. The UWB-based station tag was adopted as the detection sensor. Two arrangements were also designed to achieve fast and accurate detection of navigation parameters during the unmanned operation of agricultural machinery, including the double base station-body longitudinal double tag (TBZ) and double base station-body transverse double tag (TBH). The static test results show that the detection accuracy of navigation parameters improved significantly for the TBZ and TBH arrangements, as the tag or base station spacing increased. Specifically, the detection error of lateral deviation was ≤8 cm, and the heading deviation tended to be close to 0, but not greater than 1°. An orthogonal test was combined with the analysis of variance (ANOVA), thereby clarifying the significance of key parameters in the TBZ and TBH arrangements on the detection of lateral and heading deviation, and finally to determine the main and secondary factors for the optimal combination of parameters. The dynamic test results show that the detection accuracy of lateral and heading deviation decreased significantly, as the speed of the vehicle increased, where the error of lateral deviation was below 10 cm and the error of heading deviation was less than 3°, and the coefficient of variation was less than 10%. The finding can provide a sound reference for the development of unmanned systems with low cost, high precision, easy operation in modern mechanized agriculture. [ABSTRACT FROM AUTHOR]

This paper presents a compact triple-band and a multiband band-pass filter (BPF) using a stepped impedance line (SIL) and a modified stub-loaded open loop resonator (MSLOR), respectively. The first proposed triple-band BPF used a new technique which involves embedding the stepped impedance line (SIL) between the feed line and the open stubs. Due to this, the proposed filter achieves an ultra wideband (UWB) and two narrow bands with a fractional bandwidth of about 12.85%, 30.38% and 2.6% for use in 4G, WLAN and satellite communication. An UWB is generated with five transmission zeros that increase the high selectivity and avoid the interference between the existing bands. The second proposed filter is triple-band to multiband BPF using MSLOR. This filter achieves five passbands with seven transmission zeros. [ABSTRACT FROM AUTHOR]

In this paper, an enhanced performance E-shaped dielectric resonator antenna (DRA) with a relative permittivity of 9.2 is introduced. The new design offers a very wide operating range that extends from 3.85 to 13.3 GHz, with a fractional bandwidth of 110%. The antenna shows a stable gain (5.0–7.5 dBi) with an average efficiency of 95% across the frequency of interest. Furthermore, the antenna presents a compact volume with 30 × 40 × 11.3 mm3 dimensions, which makes it an excellent candidate for many wireless applications. The proposed design is simulated using two full-wave simulators, HFSS and CST MWS, and then measured to validate the proposed design. The simulation and measurement show very good agreement over the extended operating frequency. [ABSTRACT FROM AUTHOR]

Cognitive radio (CR) is an ultra-wideband communication system with a 50 MHz to 10 GHz frequency band that intelligently optimizes the use of the available frequency spectrum using dynamic spectrum monitoring. This paper proposes a differential ultra-wideband low-noise amplifier using two cascaded flipped-active inductors (CASFAI-LNA). The structure of each CASFAI consists of two transistors (gyrator-capacitor) and a common gate pMOS in its feedback path. The use of the capacitor cross-coupling method increases the transconductance of the circuit, which in addition to improving the gain and the noise figure, reduces the current consumption of the circuit. In addition, the biasing of active inductors from the feedback path reduces the power consumption of the circuit. This circuit is designed and validated in Cadence using a 0.18 μm CMOS process. The post-layout simulation results show that in the whole desired bandwidth (CR frequency range), the input matching is better than −10 dB, the maximum power gain is higher than 10.6 dB, the minimum noise figure is 2.24 dB, the stability factor is higher than 2.8, and the maximum IIP3 is −2.3 dBm. The proposed LNA consumes 6.12 mW from a 1.8 V DC supply. [ABSTRACT FROM AUTHOR]

In this paper, a novel compact multipleinput multiple-output (MIMO) antenna with enhanced port isolation is proposed for ultra-wideband (UWB) applications. The UWB MIMO antenna contains two coplanar annular monopoles etched on the front side of the FR-4 substrate. The dielectric substrate has a relative permittivity of 4.4 and a size of 80 mm × 40 mm × 1.6 mm. The irregular ground is printed on the back side of the substrate. In order to enhance the port isolation between the two monopoles, the expanded ground is exploited in the proposed design. In addition, the ground is etched with some slots to achieve good impedance matching. Both the simulated and measured results show that the proposed antenna achieves good impedance matching as well as high port isolation over the entire UWB band. Moreover, the proposed antenna has good spatial diversity characteristics. In summary, the proposed UWB MIMO antenna can be well applied to the ultra-wideband wireless communication system. [ABSTRACT FROM AUTHOR]

UWB suspended stripline (SSL) bandpass filter with an adjustable notched band and four transmission zeros (Tzs) is proposed here. To prevent interference signals from the wireless local‐area network (WLAN) entering UWB system, a short‐stub resonant network is introduced to this UWB filter. In addition, utilizing different resonant modes of the two short–stubs, four Tzs are generated to improve the skirt selectivity. Both the centre frequency of the notched band and the positions of Tzs can be controlled by tuning the structural parameters. The UWB SSL bandpass filter is designed, fabricated and tested. The measured results are in good agreement with the simulated results. [ABSTRACT FROM AUTHOR]

This paper presents a detailed study of multiple access ultrawideband communications based on M-ary frequency-shift keying modulation of impulse-like carrier waveforms. The proposed signal model is described using expressions of duty cycle, energy, and correlation coefficient analytically derived and analyzed in terms of signal parameters. The frequency sets for coherent as well as non coherent detection utilized in narrow band communications are extended to impulse communications, and the resultant signals' correlation properties are investigated. Analytic expression of the frequency spectrum for continuous transmission is obtained, and a parametric study of the spectrum is carried out to analyze its properties. System performance analysis in terms of error probability curves is given for different signal model parameters. For single user communications, error probability curves for M-ary system are plotted using the union bound, while for multiple access communications, analytic expression of binary error probability in Rayleigh fading channel is given and plotted. The plots demonstrate the advantages of multiple access coding and signal design in improving system performance. Comparison between the bit error performance of impulse frequency shift keying, impulse phase shift keying, pulse position, and binary phase shift keying modulation schemes is presented too. [ABSTRACT FROM AUTHOR]

In this paper, we analyze the impact of system imperfections on the overall performance of the MC-CDMA based Ultra-Wide-Band (UWB) system. A new expression of the signal-to-interference-noise ratio (SINR) for UWB Multicarrier Code division multiple access (MC-CDMA) system over a Rayleigh fading channel with imperfect power control condition are derived and investigated. The perfor- mance of MC-CDMA based UWB system over the frequency-selective multipath fading channel is examined with varying the number of users, K, the signal-to-interference-noise-ratio (SINR) per bit, Eb/N0. From the simulation results, we have seen that the SINR performance is affected by these parameters. The result of the analysis will pro- vide relevant information to design the physical layer protocol for high speed UWB 4G communications system. [ABSTRACT FROM AUTHOR]

A general approach is proposed to design ultra-wideband radar cross section reduction (RCSR) metasurface by using non-resonant unit cells in chessboard arrangement. The proposed miniaturized artificial magnetic conductor unit cell is composed of two stacked non-resonant patches separated from one another by thin dielectric substrates. The genetic optimization algorithm is used to optimize the unit cell design parameters and obtain wide 10-dB RCSR bandwidth. The proposed approach is performed to design three different RCSR metasurfaces, ideal, ROGERS and low cost. The low cost RCSR metasurface composed of low cost commercially available FR-4 substrate is fabricated and tested which reduces RCS more than 10-dB from 5.22 GHz to 30.85 GHz, 142% fractional bandwidth. This metasurface has significantly wider RCSR bandwidth rather than the state of the art references as well as low cost, simple and light weight structure which facilities its practical applications. [ABSTRACT FROM AUTHOR]

A compact ultra‐wideband (UWB) multiple‐input multiple‐output (MIMO) antenna with dual band‐notched characteristics for portable applications is proposed in this article. The antenna is fed by coplanar waveguide and has four feeding ports with the size of 50 × 50 mm2. By etching split‐ring resonator slots on the radiation patches, dual notches filtering out the 3.5 GHz WiMAX and 5.5 GHz WLAN bands can be achieved. The design process is given step‐by‐step and the band‐notched mechanism is studied with the surface current distributions. Moreover, the band‐notched characteristics of cylindrical conformal antenna is analyzed in this article. The experimental results show that the proposed antenna can be widely used in UWB communication system with good radiation characteristics, stable gain, and low envelope correlation coefficient. The idea embodied in this article can also be used to guide for the research of band‐notched conformal UWB MIMO antenna. [ABSTRACT FROM AUTHOR]

This article presents a fully integrated modular wideband frequency interleaving (FI) transmitter and receiver for high data rate communication applications. At the transmitter side, three independent in-phase and quadrature-phase (IQ) baseband channels are upconverted to different intermediate frequencies (IFs) and then interleaved. At the receiver side, the interleaved signals are downconverted and separated back to each independent channel. Single-ended inputs and outputs are utilized to reduce the pin count, for a more practical realization and higher potential toward future system scaling. Special design techniques are followed to minimize crosstalk and intermodulation products between the channels. All circuits are manufactured and measured in a 130-nm SiGe:C BiCMOS technology with $f_{\textbf {T}}/f_{\textbf {max}}$ =300/500 GHz. The FI transmitter achieves a channel bandwidth of 2.5 GHz with less than 3-dB difference across different channels until 15-GHz IF. It consumes 560 mW from 2.5 and 3.3 V supplies and occupies a silicon area of 1.9 mm2. The FI receiver achieves a baseband channel bandwidth of 2.5 GHz with a 1-dB difference between the channels until the same IF. It consumes 860 mW from 2.5 and 3.3 V supplies and has a chip area of 1.55 mm2. The circuits are deployed in a communication experiment; first, in a back-to-back test with a direct cable connection, demonstrating a data rate of 15.6 Gb/s across the three IQ channels with a 16-QAM modulation scheme and a worst case transmitter-to-receiver error vector magnitude (EVM) of −18.6 dB. Then, a wireless experiment is performed with a 240-GHz front end with on-chip antenna, demonstrating a data rate of 7.8 Gb/s with QPSK modulation and a worst case EVM of −8.3 dB, across a wireless link of 15 cm. To the best of our knowledge, this is the first article that demonstrates a wireless transmission at sub-terahertz (sub-THz) carrier frequencies utilizing FI architectures. [ABSTRACT FROM AUTHOR]

In this paper, a simple and compact UWB (ultra wideband) antenna with band-notched characteristic is proposed. The antenna operates from 3.1 to 11 GHz covering the entire UWB band (3.1–10.6 GHz) and rejects the 5.15–5.825-GHz frequency band, which is limited by IEEE 802.11a standard. The proposed antenna has a small size of 29 × 33 mm2 and is designed on an FR4 substrate with permittivity (εr) 4.5 having a thickness of 1.52 mm. A parametric study is presented to understand the resonant behaviour and its dependence on various dimensions of the antenna. The antenna is fabricated with the optimised parameters taken from the parametric study and a good agreement between the simulated and measured values is observed. [ABSTRACT FROM AUTHOR]

A microfabricated planar 0.22 THz TWT is being investigated as a high power, broadband amplifier for ultra-broadband wireless communication, imaging and remote sensing. Planar staggered double-vane-loaded rectangular waveguide slow wave structure (SDV-SWS) is selected for the 0.22 THz TWT because of its wide bandwidth, high impedance and low loss, easy fabrication using MEMS technologies with high precision and surface finish, and inherent compatibility for operation with sheet electron beam. A simplified approach is presented for determining initial design parameters of the SDV-SWS of wide bandwidth and high impedance. The initial design parameters of the SDV-SWS are used for analytically determining the dispersion and the impedance characteristics of the structure which are found comparable with the simulated characteristics by the 3D e.m. field simulator CST code. The SDV-SWS is designed for a planar 0.22 THz TWT with a sheet beam of beam voltage 20 kV and beam current 100 mA. In-house developed large signal analysis code (SUNRAY-p) is used to analyse RF performance of the planar TWT over the band. The RF performance of the 0.22 THz TWT as determined using SUNRAY-p code is found comparable with the simulated results by the CST code over the frequency band. [ABSTRACT FROM AUTHOR]

Dual carrier modulation (DCM) using orthogonal frequency-division multiplexing (OFDM) improves the performance in multipath fading channels. In the literature DCM is proposed with 16-quadrature amplitude modulation (16QAM) for ultra-wideband (UWB) communication, with four bits per symbol to keep reliable high date transmission over longer distances. Body area network (BAN) standards address transmission reliability more than data rate. UWB is one of the physical layers proposed in BAN standards. In this study, DCM is used with quadrature phase shift keying (QPSK) instead of 16QAM to have better performance in reliable transmission. The performance of QPSK-DCM is analyzed and compared with 16QAM-DCM, QPSK-OFDM, and 16QAM-OFDM in a wireless body area network channel. These simulation results are given as bit error rate (BER) versus signal to noise ratio per bit (Eb/N0) graphs. Additionally, derivations of theoretical BER - Eb/N0 performances of QPSK-OFDM and 16QAM-DCM in an additive white Gaussian noise (AWGN) channel are given. [ABSTRACT FROM AUTHOR]

Highlights • New orthogonal UWB pulses. • Sturm–Liouville theory. • High utilization efficiency. Abstract The problem of designing UWB pulses which meet specific spectrum requirements is usually treated by filtering common pulses such as Gaussian doublets, modified Hermite polynomials and wavelets. When there is the need to have a number of orthogonal pulses (e.g. , in a multiuser scenario), a naive approach is to filter all the members of an orthogonal set, which is likely to destroy their orthogonality property. In this paper, we study the design of a set of pulses that simultaneously satisfy the orthogonality property and spectrum requirements. Our design is based on the eigenfunctions of Sturm–Liouville boundary value problems. Indeed, we introduce Sturm–Liouville differential equations for which the eigenfunctions meet the FCC mask constraints. Computer simulation results show that all such waveforms occupy almost 55% of the allowed spectrum (utilization efficiency). A comparison of the proposed method with some conventional techniques of orthogonal UWB pulse generation will demonstrate the advantages of the new proposal. [ABSTRACT FROM AUTHOR]

We present here a compact liquid crystal (LC) based tunable notch filter with a narrow 3 dB bandwidth and a high quality factor. The structure of the proposed filter consists of two embedded resonators in serial, with an impedance adaptor and linear taper at each port. The notch filter combines tunable dielectric material LC with inverted microstrip technology, and was designed, fabricated and characterized to deliver a continuously tuned rejection frequency range from 3.545 GHz to 3.731 GHz, together with a narrow 3 dB bandwidth of ∼ 0.8 GHz and a high quality factor of ∼ 4.6. Such a notch filter is both compact (41 mm × 13 mm) and light weight (18.08 grams, including SMA connectors). It is suitable for working in the S band to suppress WiMAX signals that may cause interference in UWB communication systems. The narrow stopband and high quality factor of the device can be further improved at the expense of a certain extent of tuning efficiency, by using a thicker LC layer, and this is verified in experiment. The measured results of the proposed devices confirm the feasibility of using the current LC technology to manufacture tunable notch filters with a narrow bandwidth and a high quality factor. [ABSTRACT FROM AUTHOR]

Aiming at solving the problem of wireless communications within the enclosed metal cabin, such as, spacecraft and aircraft cabin, the enclosed metal cabin statistical channel parameters are given based on channel measurements which prove the channel characteristics of the strong multipath channel environments. Ultra-wideband wireless communications technology is suitable to apply in such enclosed metal cabin with the strong anti-multipath ability. Due to the extremely wide bandwidth, design and implementation of synchronization with low complexity is important for the receiver. In this paper, an improved parallel synchronization scheme consists of 1-bit quantization and multipath energy accumulation is proposed. Owing to 1-bit quantization, the computation of correlation can be simplified by transferring complex operation of multiplication into the easy operation of addition in FPGA. The synchronization performance is observed through analytical expressions corroborated by simulations which show that the 1-bit quantization can reduce the complexity significantly with a little loss in signal noise ratio. By investigating the probabilities of false alarm and missed detection in simulation, the optical threshold of synchronization is also obtained. On this basis, the hardware implementation of the physical layer algorithm and the experimental verification in the enclosed metal cabin are performed. Experiments show that the design of synchronization scheme can overcome the strong multipath effect and achieve large capacity and low bit error rate transmission. [ABSTRACT FROM AUTHOR]

Abstract A compact, circular UWB fractal antenna with triple reconfigurable notch rejection bands is proposed. It rejects the crowded frequency bands WiMAX, WLAN and X band interferences produced in UWB communication systems. The proposed fractal structure consists of a basic circular patch with circular fractal iterations. By employing this new structure of fractals, the overall size of antenna is reduced 53% to 21 × 25 mm, in comparison with traditional circular monopole antenna. The implemented antenna operates at 3.1–10 GHz. Re-configurability is realized by designing slots and split ring resonators in desired frequencies with the attached PIN diodes. WLAN band rejection was realized by creating a pair of optimized L-shaped slots in the ground plane. By etching a split ring resonator and a U-shaped slot, X and WiMAX bands were also rejected. Furthermore, by attaching diodes to aforementioned slots and designating the diodes on/off, different bands can be included or rejected. In time domain, the antenna properties are evaluated by a figure of merit called fidelity factor. Finally, the antenna properties are measured in anechoic chamber and the results agrees with simulation findings. [ABSTRACT FROM AUTHOR]

This article presents a VCO‐based impulse generator, in which all circuit blocks are switched for low power consumption. A switching control pulse generator is employed for adjusting the impulse duration. The drive amplifier can generate triangular‐like impulse with high amount of side‐lobe rejection without any external filter. The experimental results show that the frequency range covers 6.5‐9.3 GHz and 10‐dB bandwidth is tunable from 0.5‐2 GHz, while consuming only 39.6 pJ/pulse at 10 MHz pulse repetition frequency. The impulse generator is fabricated using a 0.13 μm CMOS process and chip size is 1.07 × 1.50 mm2 including ESD pads. [ABSTRACT FROM AUTHOR]

This paper presents a new miniaturized ultra-wideband (UWB) multilayer balanced bandpass filter (BPF) using the liquid-crystal polymer technology. The design is based on the use of two baluns and uses the transversal signal-interference concept for the realization of differential-mode (DM) passband and common-mode (CM) stopband. The broadside coupled stripline structure is adopted in this paper to realize UWB performances and pure TEM mode. The fabricated prototype is self-packaged, light in weight, and cost effective with a small footprint. The demonstrated balanced BPF achieves the excellent DM and CM responses within the entire bandwidth, centered at 6.85 GHz. The simulation and measurement results show good agreement. [ABSTRACT FROM AUTHOR]

This paper presents an experimental and analytical investigation of ultra-wideband (3–8 GHz) body-to-body (B-to-B) channel characterization. The channel parameters obtained are compared with off-body (off-B) and no-body (no-B) links. Measurements have been carried out considering different body positions and orientation of the Tx–Rx pair. The type of channel link and position of the wearable antenna lead to significant changes in the radio link channel. Path loss (PL) computed shows the increase in magnitude for non line of sight (NLOS) in comparison to line of sight (LOS), though the variation over a distance of 5 m is more significant for LOS (10 dB) than NLOS links (4–5 dB). For total NLOS links, B-to-B channels have slightly higher PL and delay spread parameters in comparison to off-B channel. The B-to-B LOS channels have least PL (44–56 dB), rms delay spread (0.5–4 ns), and multipath components (3–20) which can be attributed to the directional radiation pattern due to the presence of the human body for both Tx and Rx nodes. For back-to-back antenna orientation of the B-to-B channel, maximum signal strength degradation and multipath are observed. It can be concluded that for certain links, the B-to-B channel shows a significant change in channel behavior in comparison to off-B/no-B scenario. [ABSTRACT FROM AUTHOR]

This study presents a new slitted electromagnetic bandgap (EBG) structure to filter undesired wireless local area network (WLAN) and worldwide interoperability for microwave access (WiMAX) bands in the ultra‐wideband (UWB) spectrum. A simple UWB antenna which consists of a microstrip tapered feed line, a circular patch and a defected ground structure is used as a reference antenna. The antenna is then integrated with a slitted EBG structure near the feed line to notch two interfering bands. The created notched bands by the EBG structure can be independently controlled. Owing to structural symmetry of the proposed antenna, the size can be reduced by approximately half to form a miniaturised antenna. The miniaturised antenna has the same full‐size antenna characteristics with little change in the notched bands specifications. Frequency domain measurement results show that the full‐size and miniaturised antennas have a flat transfer function, and a group delay variation of about 0.5 ns in the entire UWB band except for the notched bands. [ABSTRACT FROM AUTHOR]

An Ultra-wideband (UWB) bandpass filter with three notch bands based on multi-tone waveform and Stimulated Brillouin scattering (SBS) is proposed and demonstrated. The phase modulation (PM) and tunable optical bandpass filter (TOBF) of the system are used to implement a single bandpass filter. The SBS attenuation of the multi-pump generates three notch bands and the proposed filter can efficiently reduce the interference from undesired signals at 3.5 GHz in WiMAX, 5.7 GHz in WLAN and 8 GHz in satellite. The rejection ratio of notch bands can be optimized to 36 dB, 38 dB and 35 dB. [ABSTRACT FROM AUTHOR]

The present work shows a compact size coplanar waveguide (CPW) fed antenna for ultra-wideband (UWB) communication. The designed antenna has a dimension of 20 × 20 × 1.5 mm3. The proposed antenna design comprises of a slotted rectangular patch etched on an inexpensive FR4 substrate. The proposed antenna offers a good impedance matching over a frequency range of 5.7 - 8 GHz. The characteristic parameters such as return loss, VSWR, radiation pattern and input impedance are analyzed using HFSS 11.0. Designed antenna is fabricated and tested. This antenna is found to be appropriate for various IoT based applications. [ABSTRACT FROM AUTHOR]

Non-line-of-sight (NLOS) propagation of radio signals can significantly degrade the performance of ultra-wideband localization systems indoors, it is hence crucial to mitigate the NLOS effect to enhance the accuracy of positioning. The existing NLOS mitigation algorithms to improve localization accuracy are either by compensating range errors through NLOS identification and mitigation methods for ranging or by using dedicated localization techniques. However, they are only applicable to some specific scenarios due to some special assumptions or the need of a priori knowledge, such as thresholds and distribution functions. Another disadvantage is that they neither have the capability to evaluate the magnitude of NLOS effect nor take account of the residual NLOS range errors during location estimation. To remedy these problems, this paper proposes a less environment-dependent and a priori knowledge-independent NLOS identification and mitigation method for ranging which is able to determine the specific NLOS channel. Based on the identified channel information, a rule is developed to select appropriate NLOS ranges for location estimation. Meanwhile, an equality constrained Taylor series robust least squares (ECTSRLS) technique is proposed to suppress residual NLOS range errors by introducing robustness to Taylor series least squares method. All these constitute our FCE-ECTSRLS NLOS mitigation algorithm. The performance of the proposed algorithm is compared with four existing NLOS mitigation algorithms by both static and mobile localization experiments in a harsh indoor environment. Experimental results have demonstrated that the proposed FCE-ECTSRLS algorithm outperforms the other four algorithms significantly. [ABSTRACT FROM AUTHOR]

In this paper, we propose a deterministic signal-matched sparse measurement matrix for ultra wideband (UWB) systems. The proposed matrix is easy to implement and is computationally efficient as needed in a practical system. The proposed matrix captures higher signal energy in the compressive sensing (CS) domain as compared to the commonly used random matrices. Furthermore, a simple OneShot signal recovery of a full (Nyquist rate) signal from its sub-Nyquist rate measurement samples is proposed for symbol detection. Theoretical analysis and simulation results demonstrate that the detection performance of a CS-based UWB receiver using the proposed matrix is better than the random measurement matrices and is close to a conventional system sampled at full Nyquist rate. [ABSTRACT FROM AUTHOR]