A Reconfigurable UWB Bandpass Filters with Embedded Multi-Mode Resonators

The two proposed filters described here satisfy the Federal Communications Commission Ultra-wideband (FCC-UWB) specifications and also control the center frequency and bandwidth of the filters passband. These filters consist of two distinguishing parts, Electromagnetic bandgap (EBG)-embedded multiple- mode resonator (MMR) and interdigital coupled lines to realize high performance in the operation band with a compact size of 14.0 mm × 10.1 mm. The main advantage of the two proposed filters is that three different bands are tuned. The 1st tuned band is from 3.5 GHz to 11.4 GHz for the first filter and from 3.1 GHz to 11.6 GHz for the second proposed filter, respectively. The 2nd tuned band is from 3.5 GHz to 7.5 GHz for the first filter and from 3.1 GHz to 7.8 GHz for the second proposed filter, respectively. While the 3rd tuned band of the first proposed filter is from 3.5 GHz to 5.9 GHz and from 3.1 GHz to 5.8 GHz for the second proposed filter. The bandwidth of the filters can be changed by increasing the length of the outer open circuited stubs which are controlled by using switching matrix equipment (mini circuit, replacement of PIN diodes). To validate the design theory, a reconfigurable UWB bandpass filters (BPFs) with EBG Embedded MMR are designed, fabricated and measured. Good agreement is found between simulated and measured results.

HUID:DBN-Based Fingerprint Localization and Tracking System with Hybrid UWB and IMU

High-precision localization technology is attracting widespread attention in harsh indoor environments.In this paper,we present a fingerprint localization and tracking system to estimate the locations of the tag based on a deep belief network(DBN).In this system,we propose using coefficients as fingerprints to combine the ultra-wideband(UWB)and inertial measurement unit(IMU)estimation linearly,termed as a HUID system.In particular,the fingerprints are trained by a DBN and estimated by a radial basis function(RBF).However,UWB-based estimation via a trilateral method is severely affected by the non-line-of-sight(NLoS)problem,which limits the localization precision.To tackle this problem,we adopt the random forest classifier to identify line-of-sight(LoS)and NLoS conditions.Then,we adopt the random forest regressor to mitigate ranging errors based on the identification results for improving UWB localization precision.The experimental results show that the mean square error(MSE)of the localization error for the proposed HUID system reduces by 12.96%,50.16%,and 64.92%compared with that of the existing extended Kalman filter(EKF),single UWB,and single IMU estimation methods,respectively.

一种具有陷波特性的多模态频率可重构UWB天线

为了应对在超宽带(Ultra-Wide Band, UWB)系统中频率可重构天线尺寸偏大、模式单一等问题,提出了一种具有陷波特性的多模态频率可重构UWB天线。该天线通过在圆形单极子的辐射贴片上添加T型枝节和刻蚀I型槽、倒U型槽,以获得UWB覆盖范围为2.7~11.6 GHz的宽阻抗带宽,并产生四个陷波带。仿真与实测表明:控制PIN二极管的偏置状态,可以实现单频段、双频段、三频段、四频段和五频段共五种频段下八种工作模式的多模态切换。此天线大小为16 mm×19 mm,较传统单极子天线体积减小了40%以上,实现了小型化。天线的最大增益为4.13 dBi,具有良好的辐射特性。

Zero-Index Metamaterial Superstrates UWB Antenna for Microwave Imaging Detection

Metamaterials(MTM)can enhance the properties of microwaves and also exceed some limitations of devices used in technical practice.Note that the antenna is the element for realizing a microwave imaging(MWI)system since it is where signal transmission and absorption occur.Ultra-Wideband(UWB)antenna superstrates with MTM elements to ensure the signal transmitted from the antenna reaches the tumor and is absorbed by the same antenna.The lack of conventional head imaging techniques,for instance,Magnetic Resonance Imaging(MRI)and Computerized Tomography(CT)-scan,has been demonstrated in the paper focusing on the point of failure of these techniques for prompt diagnosis and portable systems.Furthermore,the importance ofMWIhas been addressed elaborately to portray its effectiveness and aptness for a primary tumor diagnosis.Other than that,MTM element designs have been discussed thoroughly based on their performances towards the contributions to the better image resolution of MWI with detailed reasonings.This paper proposes the novel design of a Zeroindex Split RingResonator(SRR)MTMelement superstrate with a UWB antenna implemented in MWI systems for detecting tumor.The novel design of the MTM enables the realization of a high gain of a superstrate UWB antenna with the highest gain of 5.70 dB.Besides that,the MTM imitates the conduct of the zeroreflection phase on the resonance frequency,which does not exist.An antenna with an MTM unit is of a 7×4 and 10×5 Zero-index SRR MTM element that acts as a superstrate plane to the antenna.Apart from that,Rogers(RT5880)substrate material is employed to fabricate the designed MTM unit cell,with the following characteristics:0.51mm thickness,the loss tangent of 0.02,as well as the relative permittivity of 2.2,with Computer Simulation Technology(CST)performing the simulation and design.Both MTM unit cells of 7×4 and 10×5 attained 0°with respect to the reflection phase at the 2.70 GHz frequency band.The first design,MTM Antenna Design 1,consists of a 7×4 MTM unit cell that observed a rise of 5.70 dB with a return loss(S11)−20.007 dB at 2.70 GHz frequency.The second design,MTM Antenna Design 2,consists of 10×5 MTM unit cells that recorded a gain of 5.66 dB,having the return loss(S11)−19.734 dB at 2.70 GHz frequency.Comparing these two MTM elements superstrates with the antenna,one can notice that the 7×4 MTM element shape has a low number of the unit cell with high gain and is a better choice than the 10×5 MTM element in realizing MTM element superstrates antenna for MWI.

一种小型化双陷波可重构UWB天线设计

提出了一种小型化的双陷波可重构超宽带(ultra wide band,UWB)天线,通过在辐射贴片上刻蚀大、小两个C形槽,实现5G(3.3~4.4 GHz)/WiMAX(3.3~3.6 GHz)和WLAN(5.150~5.825 GHz)两个频段的陷波.采用两个PIN二极管跨接在C形槽上,通过控制PIN二极管的通断状态,在两个频段上实现陷波可重构.为了实现小型化,天线采用削顶圆形结构的辐射贴片,并将C形槽设计为嵌套结构,天线最终尺寸为18.0 mm×19.5 mm.仿真与测量结果表明:天线可以在UWB、两种单陷波和双陷波共四种状态下工作,UWB频段为3.1~11.0 GHz,两个单陷波频段分别为3.2~4.9 GHz、5.2~6.0 GHz,双陷波频段为3.25~4.75 GHz和5.3~6.1 GHz.天线的最大增益为2.8 dBi,具有良好的辐射特性.

基于编码和干涉效应的可重构UWB信号产生

提出了一种基于不同编码方案和马赫-曾德尔干涉(MZI)效应的可重构超宽带(UWB)信号产生方案。仿真和实验结果表明,仅仅通过改变编码器的编码规则,即可实现正、负高斯单边带(monocycle)脉冲和正、负近似高斯双边带(Quasi-doublet)脉冲。

芯片级超宽带可重构阵列系统的架构设计

阐述基于软件无线电的先进芯片集成工艺,对不同功能射频系统的子模块进行芯片级系统级封装(SiP)架构研究,从而满足未来通信装备对超宽带、可重构阵列、小型化的要求。

Design of a Compact Monopole Antenna for UWB Applications

In this paper,a low cost,highly efficient and low profile monopole antenna for ultra-wideband(UWB)applications is presented.A new inverted triangular-shape structure possessing meander lines is designed to achieve a wideband response and high efficiency.To design the proposed structure,three steps are utilized to achieve an UWB response.The bandwidth of the proposed antenna is improved with changing meander lines parameters,miniaturization of the ground width and optimization of the feeding line.The measured and simulated frequency band ranges from 3.2 to 12 GHz,while the radiation patterns are measured at 4,5.3,6 and 8 GHz frequency bands.The overall volume of the proposed antenna is 26×25×1.6 mm^(3);whereas the FR4 material is used as a substrate with a relative permittivity and loss tangent of 4.3 and 0.025,correspondingly.The peak gain of 4 dB is achieved with a radiation efficiency of 80 to 98%for the entire wideband.Design modelling of proposed antenna is performed in ANSYS HFSS 13 software.A decent consistency between the simulated and measured results is accomplished which shows that the proposed antenna is a potential candidate for the UWB applications.

UWB Channel Modeling and Simulation with Continuous Frequency Response

Ultra-wideband(UWB)technology is a prospective technology for high-rate transmission and accurate localization in the future communication systems.State-of-art channel modeling approaches usually divide the UWB channel into several sub-band channels and model them independently.By considering frequency-dependent channel parameters,a novel analytical UWB channel model with continuous frequency response is proposed.The composite effect of all frequency components within the UWB channel on the channel impulse response(CIR)of delay domain is derived based on the continuous channel transfer function(CTF)of frequency domain.On this basis,a closed-form simulation model for UWB channels and geometry-based parameter calculation method are developed,which can guarantee the continuity of channel characteristics on the frequency domain and greatly reduce the simulation complexity.Finally,the proposed method is applied to generate UWB channel with 2 GHz bandwidth at sub-6GHz and millimeter wave(mmWave)bands,respectively.The channel measurements are also carried out to validate the proposed method.The simulated CIR and power gain are shown to be in good agreement with the measurement data.Moreover,the comparison results of power gain and Doppler power spectral density(DPSD)show that the proposed UWB channel model Received:Apr.23,2022 Revised:Jun.09,2022 Editor:Wei Fan achieves a good balance between the simulation accuracy and efficiency.

High-resolution digital beamforming of UWB signals based on Carathéodory representation for delay compensation and array extrapolation

To realize high-resolution digital beamforming(DBF)of ultra-wideband(UWB) signals, we propose a DBF method based on Carath ′eodory representation for delay compensation and array extrapolation. Delay compensation by Carath ′eodory representation could achieve high interpolation accuracy while using the single channel sampling technique. Array extrapolation by Carath ′eodory representation reformulates and extends each snapshot, consequently extends the aperture of the original uniform linear array(ULA) by several times and provides a better realtime performance than the existing aperture extrapolation utilizing vector extrapolation based on the two dimensional autoregressive(2-D AR) model. The UWB linear frequency modulated(LFM) signal is used for simulation analysis. Simulation results demonstrate that the proposed method is featured by a much higher spatial resolution than traditional DBF methods and lower sidelobes than using Lagrange fractional filters.

Design of sextuple-mode triple-ring HTS UWB filter using two-round interpolation

A single-stage ring resonator capable of introducing six modes within the ultra-wideband(UWB)passband is presented.The sextuple-mode resonator consists of three rings and three sets of stepped-impedance open stubs.Based on this sextuple-mode resonator,a UWB filter fed by the interdigital-coupling line(ICL)is designed.And we propose a two-round interpolation method to obtain the filter's initial dimensions.The designed filter is fabricated on a double-sided YBCO/MgO/YBCO high-temperature superconducting(HTS)thin film for demonstration.The experimental results show that this UWB filter produces eight resonances in the passband eventually,which effectively improves the in-band reflection and the band-edge steepness.Moreover,the upper stopband performance is enhanced due to the transmission zeros(TZs)generated by the stepped-impedance open stubs and the ICL structure.The measured good performance verifies the practicability of the two-round interpolation approach,which can also be extended to other odd-even-mode filter designs.

Integration Interval Determination and Decision Threshold Optimization for Improved TRPC-UWB Communication Systems

Integration interval and decision threshold issues were investigated for improved transmitted reference pulse cluster （iTRPC-） ultra-wideband （UWB） systems. Our analysis shows that the bit error rate （BER） performance of iTRPC-UWB systems can be significantly improved via integration interval determination （IID） and decision threshold optimization. For this purpose, two modifications can be made at the autocorrelation receiver as follows. Firstly, the liD processing is performed for autocorrelation operation to capture multi-path energy as much as possible. Secondly, adaptive decision threshold （ADT） instead of zero decision threshold （ZDT）, is used as estimated optimal decision threshold for symbol detection. Performance of iTRPCUWB systems using liD and ADT was evaluated in realistic IEEE 802.15.4a UWB channel models and the simulation results demonstrated our theoretical analysis.

UWB SAR RFI SUPPRESSION BASED ON REGION OF SUPPORT IN 2-D WAVENUMBER DOMAIN

Radio Frequency Interference (RFI) degrades the quality of focused Ultra-WideBand Syn- thetic Aperture Radar (UWB SAR) images. From both the theoretical analysis and real data valida- tion, it is concluded that target echo and RFI have different Region Of Support (ROS) in 2-D fast- time wavenumber and aperture wavenumber domain. Consequently, a novel adaptive filter is pro- posed according to the Wiener optimum criterion on the distinct ROS characteristics of target echo and RFI. Compared with the notch filter and the Least Mean Square (LMS) adaptive filter in previ- ous literatures, the proposed method is more computationally efficient with satisfactory suppression results. In terms of Signal-to-Interference Ratio Improvement (SIRI) and processing time, the per- formance of the proposed adaptive filter is verified with the field data collected with a UWB SAR system.

ANALYSIS OF WEIGHTED NON-COHERENT RECEIVER FOR UWB-OOK SIGNAL IN MULTIPATH CHANNELS

Non-coherent receivers are attractive for pulsed Ultra-WideBand (UWB) systems due to the implementation simplicity. However, they have to face the shortage of performance degradation. Several techniques were proposed to alleviate the noise effect and promote the receiver performance, among which is the weighted combining of multiple integration sub-intervals. In this paper, the performance of the weighted non-coherent receiver for UWB On-Off Keying (UWB-OOK) signal in multipath channels is analyzed, in terms of bit-error-rate. In addition, a closed-form expression of the approximately near-optimal weighting coefficient set is derived, and two simple weighting coefficient sets are proposed as well. Finally, the analytic results are verified via the computer simulations, which reveal obvious performance improvements to the conventional energy detector.

Design and Simulation of Sub-Nanosecond Pulse Generator for Ultra-Wideband Communication

A new sub-nanosecond pulse generator scheme is proposed in the opinion of frequency field in this paper. The filtering techniques used in the UWB (ultra-wideband) generator make the circuit simple and suitable for integration. The theoretical analysis and simulation results show that monocycle form generated in the scheme have a good balance between positive and negative shape and small traipse by circuit parameter control and has improved the quality of UWB pulse form.

Comparison of Kurtosis and Fourth Power Detectors with Applications to IR-UWB OOK Systems

On-off keying (OOK) is one of the modulation schemes for non-coherent impulse radio Ultra-wideband systems. In this paper, the utilization of the kurtosis detector (KD) and fourth power detector (FD) receivers for OOK signaling is introduced. We investigate the effect of integration interval and the optimum threshold on the performance of energy detector (ED), KD and FD receivers. The semi analytic expression of BER is obtained by using generalized extreme value distribution function for KD and FD receivers. From performance point of view, the simulation results show that FD receiver outperforms KD and ED receivers. In contrast, the sensitivity to the optimum threshold is greatly reduced in KD receiver compared to ED and FD receivers.

A HIGH PERFORMANCE UWB LFM WAVEFORM GENERATOR

In this paper, the design and implementation of a high performance Ultra-WideBand (UWB) Linear Frequency Modulation (LFM) waveform generator at Very High Frequency/Ultra High Frequency (VHF/UHF) band are introduced. Firstly, the design ideas for a high performance UWB LFM waveform generator are described. Then, a generation scheme for UWB LFM waveforms is presented according to the baseband digital generation method combining with the bandwidth ex-tension method via frequency doubling. An experimental system has been implemented and tested. The results show that the UWB LFM waveform generator achieves very high performance.

Ultra-Wideband RoF System and Its Key Technologies

The microwave photonic technology-based Ultra-Wideband (UWB) Radio over Fiber (RoF) system is an important solution to the future low-cost and high-performance ultra-wideband wireless access network.Much research work has been done in this field with abundant results.This article introduces the RoF system that is based on the all-optical vector modulation technology to further enhance signal’s spectrum efficiency;the full-duplex RoF system that is based on the millimeter wave Phase-Shift Keying (PSK) modulation to greatly simplify base station structure and fiber layout;and the RoF system that is based on multi-service mixed transmission to carry the service with both wired signal and several wireless signals.The article also presents an RoF-based high-definition video transmission platform.

FAST SYMBOL-LEVEL SYNCHRONIZATION FOR TR-UWB SIGNALS USING DOUBLE HYBRID DS-TH SPREADING

A Transmitted Reference (TR) Ultra WideBand (UWB) signal with double hybrid Direct Sequence and Time Hopping (DS-TH) spreading is proposed and its symbol-level synchronization scheme is designed and analyzed. The proposed signaling format can significantly reduce the search space while reducing the spectral lines and eliminating inter-frame interference and multi-user inter- ference. Detailed analysis of the proposed scheme is carried out. Synchronization performance of the proposed signaling format in multipath channel is derived and supported by computer simulation. The search step which is closely associated with the delay of data modulated pulses is analyzed. Using the TH code, the proposed signaling format and synchronization scheme especially works well in moderate and low data rate systems.

A NEW MODULATION SCHEME FOR IR-UWB COMMUNICATION SYSTEMS

Since the poor performance of orthogonal binary Pulse Position Modulation (PPM) compared with binary Pulse Amplitude Modulation (PAM), this paper presents a new modulation scheme named Pulse Width Modulation (PWM) for Impulse Radio Ultra-WideBand (IR-UWB) communication systems. This modulation scheme uses pulses with equal amplitude and different widths to carry different information. The receiver employs differences between similarity coefficients among these pulses to distinguish different information. Both theoretical analysis and simulation results verify that this novel scheme has a Signal to Noise Ratio (SNR) gain of about 1.75 dB compared with or- thogonal binary PPM, and has an SNR loss of about 1.4 dB compared with binary PAM. Although both the theoretical analysis and simulations are based on time-hopping multiple access, this modulation scheme can also be applied to other accessing techniques of UWB communication systems.