The Experts below are selected from a list of 7806 Experts worldwide ranked by ideXlab platform
Gabriel M. Rebeiz - One of the best experts on this subject based on the ideXlab platform.
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interwoven feeding networks with aperture sinc distribution for limited scan Phased arrays and reduced number of Phase Shifters
IEEE Transactions on Antennas and Propagation, 2018Co-Authors: Bilgehan Avser, Richard F Frazita, Gabriel M. RebeizAbstract:A Phased-array feeding network that scans a limited region in space with low-sidelobe levels and a low number of Phase Shifters is investigated. The interwoven coupling network is composed of power dividers, couplers, and resistive attenuators with each Phase shifter feeding all of the antennas and creating a sinc-like current distribution over the array. This results in a boxcar function-like element pattern and suppresses the grating lobes. The width of the scan region is controlled by the interelement spacing and the coupling and attenuation coefficients of the interwoven network. Different configurations along with theoretical limitations are investigated to determine the scanable region, sidelobe level, and power loss. Two prototype linear arrays with 28 elements are fabricated at 7.9 GHz. The first array employs 14 Phase Shifters, has a half power beamwidth (HPBW) of 4°, and can scan up to ±24° with sidelobe levels less than −15 dB. The second array uses seven Phase Shifters, has an HPBW of 4°, and can scan up to ±11° with sidelobe levels less than −15 dB. Both of these arrays show state-of-the-art performance in terms of reducing the number of Phase Shifters while resulting in low sidelobe levels over the entire scan region.
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An Electronically-scanned 1.8-2.1 GHz base-station antenna using packaged high-reliability RF MEMS Phase Shifters
IEEE Transactions on Microwave Theory and Techniques, 2013Co-Authors: Chih-hsiang Ko, Kevin M.j. Ho, Gabriel M. RebeizAbstract:This paper presents the first 4-element base-station antenna that is passively scanned using low-loss RF MEMS Phase Shifters. The design is based on packaged RF MEMS SPDT switches, which are capable of handling Watts of RF power with high reliability. The results agree very well with simulations and show pattern scanning to 9° with a measured gain of 8.6-8.3 dB at 2 GHz. The array is capable of handling 5-10 W of power with no distortion.
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0.13-$\mu$m CMOS Phase Shifters for X-, Ku-, and K-Band Phased Arrays
IEEE Journal of Solid-State Circuits, 2007Co-Authors: Gabriel M. RebeizAbstract:Two 4-bit active Phase Shifters integrated with all digital control circuitry in 0.13-mum RF CMOS technology are developed for X- and Ku-band (8-18 GHz) and K-band (18-26 GHz) Phased arrays, respectively. The active digital Phase Shifters synthesize the required Phase using a Phase interpolation process by adding quadrature-Phased input signals. The designs are based on a resonance-based quadrature all-pass filter for quadrature signaling with minimum loss and wide operation bandwidth. Both Phase Shifters can change Phases with less than about 2 dB of RMS amplitude imbalance for all Phase states through an associated DAC control. For the X- and Ku-band Phase shifter, the RMS Phase error is less than 10o over the entire 5-18 GHz range. The average insertion loss ranges from to at 5-20 GHz. The input for all 4-bit Phase states is typically at -5.4 plusmn1.3 GHz in the X- and Ku-band Phase shifter. The K-band Phase shifter exhibits 6.5-13 of RMS Phase error at 15-26 GHz. The average insertion loss is from 4.6 to at 15-26 GHz. The input of the K-band Phase shifter is at 24 GHz. For both Phase Shifters, the core size excluding all the pads and the output 50 Omega matching circuits, inserted for measurement purpose only, is very small, 0.33times0.43 mm2 . The total current consumption is 5.8 mA in the X- and Ku-band Phase shifter and 7.8 mA in the K-band Phase shifter, from a 1.5 V supply voltage.
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Distributed 2- and 3-Bit W-Band MEMS Phase Shifters on Glass Substrates
IEEE Transactions on Microwave Theory and Techniques, 2004Co-Authors: Juo Jung Hung, Laurent Dussopt, Gabriel M. RebeizAbstract:This paper presents state-of-the-art RF microelectromechanical (MEMS) Phase Shifters at 75-110 GHz based on the distributed microelectromechanical transmission-line (DMTL) concept. A 3-bit DMTL Phase shifter, fabricated on a glass substrate using MEMS switches and coplanar-waveguide lines, results in an average loss of 2.7 dB at 78 GHz (0.9 dB/bit). The measured figure-of-merit performance is 93°/dB-100°/dB (equivalent to 0.9 dB/bit) of loss at 75-110 GHz. The associated Phase error is ±3° (rms Phase error is 1.56°) and the reflection loss is below -10 dB over all eight states. A 2-bit Phase shifter is also demonstrated with comparable performance to the 3-bit design. It is seen that the Phase shifter can be accurately modeled using a combination of full-wave electromagnetic and microwave circuit analysis, thereby making the design quite easy up to 110 GHz. These results represent the best Phase-shifter performance to date using any technology at W-band frequencies. Careful analysis indicates that the 75-110-GHz figure-of-merit performance becomes 150°/dB-200°/dB, and the 3-bit average insertion loss improves to 1.8-2.1 dB if the Phase shifter is fabricated on quartz substrates.
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low loss 2 and 4 bit ttd mems Phase Shifters based on sp4t switches
IEEE Transactions on Microwave Theory and Techniques, 2003Co-Authors: Guanleng Tan, Robert Mihailovich, J B Hacker, Jeffrey F Denatale, Gabriel M. RebeizAbstract:2- and 4-bit microelectromechanical system (MEMS) X- to K/sub u/-band true-time-delay Phase Shifters with a very low insertion loss are described. The Phase Shifters are fabricated on 200-/spl mu/m GaAs substrates and the low loss is achieved using MEMS SP4T switches, which reduce the number of switches in the signal path by half when compared to conventional designs with SP2T switches. Measurements indicate an insertion loss of -0.6/spl plusmn/0.3 and -1.2/spl plusmn/0.5 dB at 10 GHz for the 2- and 4-bit designs, respectively. The measured losses agreed very well with Momentum simulations and are the lowest reported to date. The 2-bit Phase shifter performed well from dc-18 GHz, with -0.8/spl plusmn/0.3-dB insertion loss at 18 GHz and a return loss of <-10.5 dB over dc-18 GHz.
Robert W Heath - One of the best experts on this subject based on the ideXlab platform.
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falp fast beam alignment in mmwave systems with low resolution Phase Shifters
IEEE Transactions on Communications, 2019Co-Authors: Nitin Jonathan Myers, Amine Mezghani, Robert W HeathAbstract:Millimeter wave (mmWave) systems can enable high data rates if the link between the transmitting and receiving radios is configured properly. Fast configuration of mmWave links, however, is challenging due to the use of large antenna arrays and hardware constraints. For example, a large amount of training overhead is incurred by exhaustive search-based beam alignment in typical mmWave Phased arrays. In this paper, we present a framework called FALP for Fast beam Alignment with Low-resolution Phase Shifters. FALP uses an efficient set of antenna weight vectors to acquire channel measurements, and allows faster beam alignment when compared to exhaustive scan. The antenna weight vectors in FALP can be realized in ultra-low power Phase Shifters whose resolution can be as low as one-bit. From a compressed sensing (CS) perspective, the CS matrix designed in FALP satisfies the restricted isometry property and allows CS algorithms to exploit the fast Fourier transform. The proposed framework also establishes a new connection between channel acquisition in Phased arrays and magnetic resonance imaging.
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falp fast beam alignment in mmwave systems with low resolution Phase Shifters
arXiv: Signal Processing, 2019Co-Authors: Nitin Jonathan Myers, Amine Mezghani, Robert W HeathAbstract:Millimeter wave (mmWave) systems can enable high data rates if the link between the transmitting and receiving radios is configured properly. Fast configuration of mmWave links, however, is challenging due to the use of large antenna arrays and hardware constraints in these systems. The large amount of training overhead incurred by exhaustive search-based beam alignment in typical mmWave systems is one common example. We present a framework for Fast beam Alignment with Low-resolution Phase Shifters which we refer to as FALP. FALP designs an efficient set of antenna weight vectors to acquire channel measurements, and allows faster beam alignment when compared to exhaustive scan. The antenna weight vectors in FALP can be realized in ultra-low power Phase Shifters whose resolution can be as low as one-bit. From a compressed sensing (CS) perspective, the CS matrix designed in FALP satisfies the restricted isometry property and allows CS algorithms to exploit the fast Fourier transform. The proposed framework also establishes a new connection between channel acquisition in Phased arrays and magnetic resonance imaging.
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hybrid mimo architectures for millimeter wave communications Phase Shifters or switches
IEEE Access, 2016Co-Authors: Roi Mendezrial, Cristian Rusu, Nuria Gonzalezprelcic, Ahmed Alkhateeb, Robert W HeathAbstract:Hybrid analog/digital multiple-input multiple-output architectures were recently proposed as an alternative for fully digital-precoding in millimeter wave wireless communication systems. This is motivated by the possible reduction in the number of RF chains and analog-to-digital converters. In these architectures, the analog processing network is usually based on variable Phase Shifters. In this paper, we propose hybrid architectures based on switching networks to reduce the complexity and the power consumption of the structures based on Phase Shifters. We define a power consumption model and use it to evaluate the energy efficiency of both structures. To estimate the complete MIMO channel, we propose an open-loop compressive channel estimation technique that is independent of the hardware used in the analog processing stage. We analyze the performance of the new estimation algorithm for hybrid architectures based on Phase Shifters and switches. Using the estimate, we develop two algorithms for the design of the hybrid combiner based on switches and analyze the achieved spectral efficiency. Finally, we study the tradeoffs between power consumption, hardware complexity, and spectral efficiency for hybrid architectures based on Phase shifting networks and switching networks. Numerical results show that architectures based on switches obtain equal or better channel estimation performance to that obtained using Phase Shifters, while reducing hardware complexity and power consumption. For equal power consumption, all the hybrid architectures provide similar spectral efficiencies.
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hybrid mimo architectures for millimeter wave communications Phase Shifters or switches
arXiv: Information Theory, 2015Co-Authors: Roi Mendezrial, Cristian Rusu, Nuria Gonzalezprelcic, Ahmed Alkhateeb, Robert W HeathAbstract:Hybrid analog/digital MIMO architectures were recently proposed as an alternative for fully-digitalprecoding in millimeter wave (mmWave) wireless communication systems. This is motivated by the possible reduction in the number of RF chains and analog-to-digital converters. In these architectures, the analog processing network is usually based on variable Phase Shifters. In this paper, we propose hybrid architectures based on switching networks to reduce the complexity and the power consumption of the structures based on Phase Shifters. We define a power consumption model and use it to evaluate the energy efficiency of both structures. To estimate the complete MIMO channel, we propose an open loop compressive channel estimation technique which is independent of the hardware used in the analog processing stage. We analyze the performance of the new estimation algorithm for hybrid architectures based on Phase Shifters and switches. Using the estimated, we develop two algorithms for the design of the hybrid combiner based on switches and analyze the achieved spectral efficiency. Finally, we study the trade-offs between power consumption, hardware complexity, and spectral efficiency for hybrid architectures based on Phase shifting networks and switching networks. Numerical results show that architectures based on switches obtain equal or better channel estimation performance to that obtained using Phase Shifters, while reducing hardware complexity and power consumption. For equal power consumption, all the hybrid architectures provide similar spectral efficiencies.
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channel estimation and hybrid combining for mmwave Phase Shifters or switches
Information Theory and Applications, 2015Co-Authors: Roi Mendezrial, Cristian Rusu, Nuria Gonzalezprelcic, Ahmed Alkhateeb, Robert W HeathAbstract:Precoding/combining and large antenna arrays are essential in millimeter wave (mmWave) systems. In traditional MIMO systems, precoding/combining is usually done digitally at baseband with one radio frequency (RF) chain and one analog-to-digital converter (ADC) per antenna. The high cost and power consumption of RF chains and ADCs at mmWave frequencies make an all-digital processing approach prohibitive. When only a limited number of RF chains is available, hybrid architectures that split the precoding/combining processing into the analog and digital domains are attractive. A previously proposed hybrid solution employs Phase Shifters and mixers in the RF precoding/combining stage. It obtains near optimal spectral efficiencies with a reduced number of RF channels. In this paper we propose a different hybrid architecture, which simplifies the hardware at the receiver by replacing the Phase Shifters with switches. We present a new approach for compressed sensing based channel estimation for the hybrid architectures. Given the channel estimate, we propose a novel algorithm that jointly designs the antenna subsets selected and the baseband combining. Using power consumption calculations and achievable rates, we compare the performance of hybrid combining with antenna switching and Phase shifting, showing that antenna selection is preferred in a range of operating conditions.
Nitin Jonathan Myers - One of the best experts on this subject based on the ideXlab platform.
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falp fast beam alignment in mmwave systems with low resolution Phase Shifters
IEEE Transactions on Communications, 2019Co-Authors: Nitin Jonathan Myers, Amine Mezghani, Robert W HeathAbstract:Millimeter wave (mmWave) systems can enable high data rates if the link between the transmitting and receiving radios is configured properly. Fast configuration of mmWave links, however, is challenging due to the use of large antenna arrays and hardware constraints. For example, a large amount of training overhead is incurred by exhaustive search-based beam alignment in typical mmWave Phased arrays. In this paper, we present a framework called FALP for Fast beam Alignment with Low-resolution Phase Shifters. FALP uses an efficient set of antenna weight vectors to acquire channel measurements, and allows faster beam alignment when compared to exhaustive scan. The antenna weight vectors in FALP can be realized in ultra-low power Phase Shifters whose resolution can be as low as one-bit. From a compressed sensing (CS) perspective, the CS matrix designed in FALP satisfies the restricted isometry property and allows CS algorithms to exploit the fast Fourier transform. The proposed framework also establishes a new connection between channel acquisition in Phased arrays and magnetic resonance imaging.
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falp fast beam alignment in mmwave systems with low resolution Phase Shifters
arXiv: Signal Processing, 2019Co-Authors: Nitin Jonathan Myers, Amine Mezghani, Robert W HeathAbstract:Millimeter wave (mmWave) systems can enable high data rates if the link between the transmitting and receiving radios is configured properly. Fast configuration of mmWave links, however, is challenging due to the use of large antenna arrays and hardware constraints in these systems. The large amount of training overhead incurred by exhaustive search-based beam alignment in typical mmWave systems is one common example. We present a framework for Fast beam Alignment with Low-resolution Phase Shifters which we refer to as FALP. FALP designs an efficient set of antenna weight vectors to acquire channel measurements, and allows faster beam alignment when compared to exhaustive scan. The antenna weight vectors in FALP can be realized in ultra-low power Phase Shifters whose resolution can be as low as one-bit. From a compressed sensing (CS) perspective, the CS matrix designed in FALP satisfies the restricted isometry property and allows CS algorithms to exploit the fast Fourier transform. The proposed framework also establishes a new connection between channel acquisition in Phased arrays and magnetic resonance imaging.
A M Abbosh - One of the best experts on this subject based on the ideXlab platform.
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Phase Shifters with wide range of Phase and ultra wideband performance using stub loaded coupled structure
IEEE Microwave and Wireless Components Letters, 2014Co-Authors: Lei Guo, A M AbboshAbstract:Compact planar Phase Shifters with wide range of differential Phase shift across ultra-wideband frequency are proposed. To achieve that performance, the devices use broadside coupled structure terminated with open-ended or short-ended stubs. The theory of operation for the proposed devices is derived. To validate the theory, several Phase Shifters are designed to achieve a differential Phase ranging from -180° to 180°. Moreover, three prototypes are developed and tested. The simulated and measured results agree well with the theory and show less than 7° Phase deviation and 1.4 dB insertion loss across the band 3.1-10.6 GHz.
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compact tunable reflection Phase Shifters using short section of coupled lines
IEEE Transactions on Microwave Theory and Techniques, 2012Co-Authors: A M AbboshAbstract:In the design of reflection-type Phase Shifters, the coupler that represents the shifter's backbone is usually assumed to be a quarter-wavelength 3-dB coupler. In this paper, a derived theoretical model shows that, for certain values for the odd- and even-mode impedances, a coupled structure with a length that is less than one tenth of a wavelength is sufficient to build a high-performance reflection Phase shifter. The presented analysis indicates that reflection Phase Shifters can be designed with a more compact size and larger Phase range compared with the conventional method of using a quarter-wavelength 3-dB coupler. However, the required odd-mode impedance in the proposed design is low (≈10 Ω) , whereas the required even-mode impedance is high (≈200 Ω). To realize those impedances when using parallel-coupled lines, slotted ground and shunt chip capacitor are used. The proposed design is supported by full-wave electromagnetic simulations and measurements. The simulated results show that 0.085λ coupled structure achieves 255° Phase range across 36% fractional bandwidth with less than 1-dB insertion loss and more than 10-dB return loss. In another design, a full-cycle Phase range is obtained with less than 1.5-dB insertion loss across the same band by using two 0.076λ coupled sections. A manufactured prototype for a full-cycle Phase range validates the simulation results and, thus, the proposed method.
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double microstrip slot transitions for broadband pm 90 circ microstrip Phase Shifters
IEEE Microwave and Wireless Components Letters, 2012Co-Authors: Yifan Wang, M E Bialkowski, A M AbboshAbstract:The letter describes double microstrip-slot transitions for use in planar ± 90° Phase Shifters. The described devices exhibit broadband performance and offer compatibility with ordinary microstrip circuits. Full-wave EM simulation results show a Phase shift of ± 90° ± 7° over the frequency band of 3.1-12.0 GHz when compared with a suitably chosen section of microstripline. The observed differential Phase shift is accompanied by return losses of not less than 14 dB and insertion losses between 0.7 to 1.5 dB in the band 3.1-11.0 GHz. The simulated performance is confirmed by experimental results of ± 90° ± 8° Phase shift, return loss not less than 14 dB and insertion loss between 0.5 and 1.8 dB in the frequency band of 3.1-11.0 GHz.
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broadband fixed Phase Shifters
IEEE Microwave and Wireless Components Letters, 2011Co-Authors: A M AbboshAbstract:A method to design planar and compact Phase Shifters with broadband characteristics is presented. It utilizes broadside-coupled microstrip-coplanar waveguide, and thus the proposed devices can be fabricated using the simple and cheap double-side printed circuit boards. The method is used to design 60° and 90° Phase Shifters. The simulated and measured results show that the developed Phase Shifters achieve 3 to 11 GHz bandwidth with low Phase instability (±2°), very low insertion loss (0.4 dB), high return loss (15 dB), and a compact size (1.5 cm × 2 cm).
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ultra wideband Phase Shifters
IEEE Transactions on Microwave Theory and Techniques, 2007Co-Authors: A M AbboshAbstract:A method with clear guidelines is presented to design compact planar Phase Shifters with ultra-wideband (UWB) characteristics. The proposed method exploits broadside coupling between top and bottom elliptical microstrip patches via an elliptical slot located in the mid layer, which forms the ground plane. A theoretical model is used to analyze performance of the proposed devices. The model shows that it is possible to design high-performance UWB Phase Shifters for the 25deg-48deg range using the proposed structure. The method is used to design 30deg and 45deg Phase Shifters that have compact size, i.e., 2.5 cm times 2 cm. The simulated and measured results show that the designed Phase Shifters achieve better than plusmn3deg differential Phase stability, less than 1-dB insertion loss, and better than 10-dB return loss across the UWB, i.e., 3.1-10.6 GHz.
Chonghu Cheng - One of the best experts on this subject based on the ideXlab platform.
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proposal and synthesis design of wideband filtering differential Phase Shifters with a pair of out of band transmission zeroes
IEEE Transactions on Microwave Theory and Techniques, 2018Co-Authors: Yunpeng Lyu, Lei Zhu, Chonghu ChengAbstract:In this paper, a new class of wideband filtering Phase Shifters with a pair of controllable out-of-band transmission zeroes is presented for the first time. The proposed wideband filtering differential Phase shifter consists of two stub-loaded multimode resonators (SLMMR) in the main and reference branches, which can provide a constant Phase shift and self-realized generalized Chebyshev filtering function with controllable transmission zeroes by properly setting the impedance ratio $R_{\mathrm {z}}$ of the loaded stub. On the one hand, the prescribed Phase shift value, Phase deviation, and Phase shift bandwidth are deduced that basically dominated by resonant modes of SLMMR together with electrical lengths of the Phase-shifting lines. On the other hand, the Phase properties of transmission zeroes are systematically investigated to demonstrate that they arouse little effect on the Phase shift performance, but highly improve the frequency selectivity in theoretical analysis. Based on the presented synthesis method which simultaneously considers wideband Phase shift and bandpass filtering function, the circuit parameters of the entire proposed Phase shifter can be synthesized with prescribed Phase shift value, Phase deviation, bandwidth, return loss, and transmission zero positions. Besides, the Phase shift and return loss bandwidth can be determined in the design process. As design examples, two 90° wideband filtering Phase Shifters with different specifications are synthesized, designed, and fabricated to validate our proposed approach.
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proposal and synthesis design of differential Phase Shifters with filtering function
IEEE Transactions on Microwave Theory and Techniques, 2017Co-Authors: Yunpeng Lyu, Lei Zhu, Chonghu ChengAbstract:In this paper, a new class of filtering differential Phase Shifters is proposed and developed, which can provide constant Phase shift and self-embedded filtering function at the same time. In contrast to its traditional counterparts, the proposed Phase shifter consists of two bandpass filter (BPF) branches and the Phase properties of generalized ${n}$ th-order BPF network are systematically studied at first time. With derived closed-form formula of Phase slope, the synthesis method is presented to design the proposed filtering differential Phase Shifters with prescribed arbitrary Phase shift value, passband ripple, and bandwidth. The filter order, which dominates frequency selectivity, is considered in the synthesis design of proposed Phase shifter as well. The tradeoff between the frequency selectivity and Phase shift is discussed. In addition to the advanced features of multifunction and simple geometry, the proposed filtering differential Phase Shifters can achieve compact size, low amplitude imbalance, and multiway polyPhase capability. To validate the proposed concept and synthesis method, two filtering differential Phase Shifters with single-Phase (90°) and five-way polyPhase (45°, 90°, 135°, and 180°) are designed, fabricated, and measured. The simulated and measured results coincide well with the prescribed performances in Phase shift and magnitude.
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proposal and synthesis design of wideband Phase Shifters on multimode resonator
IEEE Transactions on Microwave Theory and Techniques, 2016Co-Authors: Yunpeng Lyu, Lei Zhu, Chonghu ChengAbstract:In this paper, a new class of wideband Phase Shifters on multimode resonator is proposed and developed. Compared with its conventional counterparts, these new Phase Shifters have a few advantageous features such as simple structure, intrinsic wideband characteristic, large Phase-shift value, and easy adjustment in Phase shift. The Phase properties of multimode resonator are at first studied to derive the quantitative relationship between the Phase slope and their respective resonant frequencies. On the one hand, a prescribed wideband Phase shift can be achieved by adjusting the impedance ratio $R_{z}$ of the multimode resonator and the electrical length of the reference line. On the other hand, the wide operating band can be intrinsically obtained over a frequency range covered by multiple resonant frequencies in the multimode resonator. In this context, the transmission-line models of the proposed Phase Shifters are deduced and synthesized to design these Phase Shifters with a prescribed Phase shift value and return loss within the operating band. Moreover, the synthesized model can be directly mapped into all the physical dimensions, thus allowing for a quick design process. Finally, two 180° wideband Phase Shifters are designed, fabricated, and tested to verify the proposed design method and predicted frequency responses.