Reflection Phase Shifter Research Articles

Reflection Phase Shifter Topology With 180° Tuning Range Using Impedance Transforming Coupler and Series Resonant Load for K-Band Phased Arrays

Reflection Phase Shifter Topology With 180° Tuning Range Using Impedance Transforming Coupler and Series Resonant Load for <i>K</i>-Band Phased Arrays

A sum‐rate maximization for IRS‐aided broadcast SWIPT with time‐switching structure and nonlinear energy harvester

AbstractThis study evaluates the sum‐rate gain of the intelligent reflecting surface (IRS) in a broadcast simultaneous wireless information and power transfer network. Users are equipped with a time‐switching (TS) structure for an alternating information decoder and a nonlinear energy harvester. The sum‐rate maximization (SRM) problem is formulated subject to the constraints of the energy‐harvesting threshold required by users and limited transmission power at the base station (BS). To address the SRM problem, we jointly designed a broadcast beamforming precoding vector at the BS, reflective phase shifters at the IRS, and TS factors at the users. Subsequently, after certain manipulations, we propose efficient iterative algorithms that combine alternating optimization, successive convex approximation, semidefinite relaxation, and rank‐one penalty function methods to obtain a suboptimal solution. Finally, the numerical results show the promising sum‐rate gain of the proposed scheme compared with the conventional schemes.

An Active Reconfigurable Intelligent Surface Utilizing Phase-Reconfigurable Reflection Amplifiers

Active reconfigurable intelligent surfaces (RISs) have recently been proposed to complement and generalize passive RIS. In this work, the design for an active RIS based on phase-reconfigurable reflection amplifiers is proposed. The proposed active RIS elements’ design consists of a two-layer patch antenna and a phase-reconfigurable reflection amplifier that is realized by a cascade of a phase shifter and a reflection amplifier. Theoretical and numerical analyses are used to quantify key parameters that need to be met in the design of the reflection amplifier and phase shifters. These show that a tradeoff between the reflection amplifier’s gain and the phase shifter’s return and insertion loss is required to be balanced to obtain a stable and effective overall design. In particular, a reflection amplifier with about 13-dB gain and a 2-bit phase shifter with only about 1.9-dB insertion loss and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$-$</tex-math> </inline-formula> 25-dB return loss are designed. The final RIS element obtains 8.5-dB gain with four reconfigurable phases ranging from 0 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$^{\circ}$</tex-math> </inline-formula> to 360 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$^{\circ}$</tex-math> </inline-formula> with small root mean square (rms) gain and phase errors. An active RIS can be constructed by concatenating these elements together, and an efficient analytical method to calculate the scattered pattern by the active RIS is also proposed. Experimental results for a <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$2$</tex-math> </inline-formula> <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\times$</tex-math> </inline-formula> <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$2$</tex-math> </inline-formula> element active RIS prototype are also provided. These show that the active RIS provides received powers around 8.5 dB higher than that from using an equivalent passive RIS. The results demonstrate the feasibility of achieving gain in active RISs and help demonstrate their promise as a technology for future high-capacity wireless communication systems.

Grating Lobe Suppression for Wideband Large-Spacing Beam Scanning Array Using Subarray Null Adjustable Method

In this letter, a subarray null adjustable method is proposed to solve the grating lobe problem for wideband large-spacing beam scanning arrays. With the reshaped subarray by this method, large null depths of the pattern are formed to align with the grating lobe regions. The proposed reflective phase shifter loaded four varactors adjusts these nulls continuously, accurately and flexibly. Then, a wide-angle coverage of continuous nulls sufficiently suppress grating lobes in the whole bandwith. A two-element subarray with the bandwidth of 40% (2.8–4.2 GHz) is introduced, and an 8 × 4 planar array formed by this subarray is fabricated and measured as the verification prototype. Finally, the proposed planar beam scanning array realizes grating-lobe-free scanning of ±45° in the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">yoz</i> -plane (with the array spacing of one wavelength at the highest frequency) and ±53° in the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">xoz</i> -plane over the entire wideband range, respectively.

Electrically active control of terahertz waves in a hybrid metasurface-grating structure with a liquid crystal.

A reflective terahertz phase shifter for wide-range dynamic and continuous phase modulation is proposed. By injecting a tunable liquid crystal between the slotted metasurface and the grating microstructure, the phases of reflected waves can be modulated with different electrically driven methods. Numerical simulations show that the proposed terahertz phase shifter has a phase difference of more than 360° between unbiased and biased states. Furthermore, an array of 35×35 patch elements was designed and fabricated. The performance of the phase shifter provides more than 360° between 379.6 and 391.8 GHz, where the maximum phase shift reaches 422.4° at 385.9 GHz. Moreover, the fully electrically controlled phase modulation of more than 180° is achieved between 382.0 and 394.1 GHz, with a maximum phase modulation of 248.4° at 383.3 GHz. This work may provide a reflective terahertz phase modulator for beam steering.

Design and Implementation of Phase Shifter for Wireless Communication

Abstract: Phase shifters are common microwave devices that are widely used to control the phase of a microwave signal in mobile satellite systems, microwave instrumentation and measurement systems, modulators, noise cancellation systems, frequency converters, electronic beam scanning phase arrays, microwave imaging, and many other industrial applications is used for. Phase shifters are passive devices used to perform variable phase changes in the wave propagating through it. Phase shifters require compact size, low cost and low insertion loss in the desired bandwidth. The size of the phase shifters is a crucial parameter, especially in the design of portable microwave devices, due to the space constraints. The significantly higher insertion loss of phase shifters used in a transmitter causes a significant reduction in transmitting power levels, while it causes a severe drop in signal to noise ratio when the phase shifter is a part of the receiver.. Phase shifters are essential components in phased array antennas for wireless and Radio Detection And Ranging (RADAR) applications. Loaded line phase shifter, reflective line phase shifter and switched line phase shifters are the most commonly used. The electrical performance of a phase shifter is specified in terms of insertion loss, phase error, operating bandwidth and power handling capacity.. Emerging wireless systems have transceivers that require compact and cost effective phase shifters. Physical size and weight of phase shifters are the major issues in mobile and the wireless applications. Therefore, miniaturization of phase shifters has become an important objective of radio frequency (RF) designers to provide portability and affordability in wireless/mobile systems. The present research work mainly focuses on planar phase shifter design with linear phase shift. In this a Defected Ground Structures (DGS) is proposed where as ,Monolithic Microwave Integrated Circuits (MMIC), Micro Electro Mechanical Systems (MEMS) and fractals have emerged as the possible techniques for miniaturization of RF systems and antennas. However the existence of defected cells on the ground plane may limit the use of DGS based phase shifters. MMIC technology increases the cost and complexity of manufacturing whereas MEMS based phase shifter is prone to limited life and yield. In this thesis, fractal techniques are adapted to design and develop miniaturized phase shifters for wireless applications.

Active continuous control of terahertz wave based on a reflectarray element-liquid crystal-grating electrode hybrid structure.

In this work, a new and efficient terahertz reflective phase shifter is proposed. The phase shifter is composed of a metal-dielectric-metal structure with a double dipole patch array, as well as copper grating electrodes immersed within the nematic liquid crystal. More specifically, the employed copper grating electrodes consist of two sets of cross-distributed comb grids, whereas at each set of comb grids can be applied an external bias voltage separately. On top of that, the electric field in the liquid crystal (LC) layer can be continuously changed by enforcing an innovative technique. Consequently, the orientation of the LC molecules was fully controlled by the applied electric field, since the dielectric constant of the LC is controlled by the biased voltage. The phase of the reflective electromagnetic wave can be continuously manipulated. Under this direction, the experimental results show that the phase shift exceeds the value of 180° in the range of 102.5 GHz-104.3 GHz, where the maximum phase shift is 249° at 103 GHz. The proposed work provides a new regulation concept for the implementation of LC-based terahertz devices and the respective applications in the terahertz reconfigurable antennas field.

Design and Fabrication of Reflective Phase Shifter for Two‐Dimensional Terahertz Beam‐Scanning Reflectarray

A reflective phase shifter is proposed to realize the two-dimensional beam-scanning reflectarray. The reflectarray is composed of double-dipole resonant elements in which the phase shift is implemented by applying a driving voltage to the liquid crystal (LC). A 30 × 30 phase shifter sample is fabricated on a quartz substrate with a 480 μm thickness and a 4 cm × 4 cm area. According to the experimental results, 0 to 360° phase shift can be achieved within the bandwidth of 5 GHz. In order to accomplish two-dimensional beam-scanning and reduce the negative impact of driving lines on the reflectarray, a new LC driving method is developed. To verify the accuracy of the proposed approach, three samples of different driving line numbers are designed using the above-mentioned phase shifter, which all have achieved a 0−360° phase shift in the bandwidth of 4 GHz. Considering the influence of LC anisotropy and inhomogeneity, an improved calculation result is obtained and compared with experimental data.

Design of Pattern Reconfigurable Patch Antenna Array Based on Reflective Phase-Shifter

A circularly polarized (CP) broadside antenna array with a continuously adjustable beam is proposed and implemented. First, a reflection phase shifter with varactor diodes loaded on two output terminals of a branch directional coupler is realized. By controlling the voltage across both ends of the varactor diodes in the terminal load circuit, the reactance of the load is changed, allowing control of port phase shift. Following that, the microstrip patch antenna array is combined with the reflection phase shifter to achieve the pattern reconstruction for the array. For verification, a prototype of the designed pattern reconfigurable antenna (PRA) is fabricated and measured. The measurement results indicate that the beam direction of the antenna can be continuously adjusted with a change in the voltage across the varactor diodes. The maximum beam direction of the antenna reaches ±21° when the biggest DC bias voltage across the varactor diode is chosen as 15 V. Besides, the antenna shows good CP performance in different beam directions.

Continuous Broadband GaAs and GaN MMIC Phase Shifters

We describe the design of two broadband monolithic microwave integrated circuit (MMIC) loaded-line reflective phase shifters and their performance over the 6–12-GHz band. Lange couplers with transistor-loaded transmission-line reactive loads provide variable phase shift through reverse-bias control. A GaAs phase shifter with four diode-connected transistors in each of the two reactive loads is designed with discrete inductors to provide an increasing phase shift with frequency. A GaN reflective phase shifter uses 14 transistors in each reactive load with a goal of increasing the phase shift across the band. Measurements show continuous phase shift from 40° to 70° with less than 6-dB insertion loss over the 6–10-GHz band and from 60° to 165° with less than 8-dB insertion loss across the 8–12-GHz band for the GaAs and GaN MMICs, respectively. The power performance of the MMICs is compared in terms of large-signal <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$S$ </tex-math></inline-formula> -parameters, harmonics, and IP3. The GaN phase shifter exhibits similar level of harmonic generation like the GaAs device at a 20-dB higher input power.

Air-bridged Schottky diodes for dynamically tunable millimeter-wave metamaterial phase shifters

A low loss metamaterial unit cell is presented with an integrated GaAs air-bridged Schottky diode to produce a dynamically tunable reflective phase shifter that is capable of up to 250° phase shift with an experimentally measured average loss of 6.2 dB at V-band. The air-bridged Schottky diode provides a tuneable capacitance in the range between 30 and 50 fF under an applied reverse voltage bias. This can be used to alter the resonant frequency and phase response of a split patch unit cell of a periodic metasurface. The air-bridged diode die, which is flip-chip soldered to the patch, has ultra-low parasitic capacitance and resistance. Simulated and measured results are presented which verify the potential for the attainment of diode switching speeds with acceptable losses at mmWave frequencies. Furthermore the study shows that this diode-based unit cell can be integrated into metamaterial components, which have potential applications in future mmWave antenna beam-steering, intelligent reflecting surfaces for 6G communications, reflect-arrays, transmit-arrays or holographic antennas.

A novel reconfigurable PD based on complementary hybrid circuit

ABSTRACT Reconfigurable methods including areflective phase-shifter circuit are proposed based on complementary hybrid network power divider (PD). The analysis shows that this method can achieve continuously tunable power division ratio (PDR) and wide phase difference by changing the two horizontal transmission lines of the complementary hybrid network. In this way, areconfigurable PD based on acomplementary hybrid circuit-based reflective phase-shifter is designed to work at 2.45 GHz by replacing two horizontal transmission lines with 50 Ω reflective phase-shift circuits. The PDR of this fabricated reconfigurable PD is changed to the range of −29.12 to −0.24 dB, with the bias voltage being 0–8 V; meanwhile, the return loss and isolation are better than 23.2 dB.

Mechanically Reconfigurable Linear Phased Array Antenna Based on Single-Block Waveguide Reflective Phase Shifters With Tuning Screws

This work presents the design and prototyping of a reconfigurable phased array in Ku band (16 to 18 GHz) implemented in waveguide technology. The design is based on the use of a novel seamless waveguide module integrating four reconfigurable phase shifters to adjust the relative phase shift between the unitary elements of a linear array, which are illuminated uniformly by a corporate waveguide feeding network. The phase shifters are implemented by a 90° hybrid coupler in waveguide technology where two of its ports are loaded with a tunable reactive load, implemented in this proof of concept with a tuning screw. The four phase shifters have been manufactured in a single part using direct metal laser sintering, avoiding the losses related to bad electric contacts and misalignments associated to multipart devices. This also simplifies the assembly of the full phased array, leading to a modular approach with three parts whose design can be addressed separately. The experimental results for the complete array antenna show great performance and demonstrate that the main-lobe of the radiation pattern can be effectively scanned continuously between the angles -25° and 25°, with a high efficiency in the whole design band thanks to the proposed waveguide implementation.

Microfluidically Reconfigurable Reflection Phase Shifter

A microfluidic-based reconfiguration approach is presented for realizing a reflection phase shifter. The phase shifter consists of quadrature hybrid coupler with reflective microstrip line terminations. A selectively metallized plate (SMP) that can be repositioned inside a microfluidic channel is brought in close proximity ( $\mu \text{m}$ ) of the reflective microstrip line terminations to vary their electrical lengths through capacitive RF short mechanism. The concept is demonstrated through a 9.5 GHz $X$ -band phase-shifter design. Specifically, the design exhibits a footprint of $24\times15$ mm2, operates with <0.95 dB insertion loss, and attains the 360° phase shift with a total of 9.5 mm SMP motion resulting in 1.95 s total actuation time with the selected external micropumps. These phase shifters may be suitable for applications that prioritize low-loss and high power handling capability over reconfiguration speed.

Reflective liquid crystal terahertz phase shifter with tuning range of over 360°

This study presents the design and experiment of a terahertz reflective phase shifter based on liquid crystal. The proposed voltage-tunable phase shifter takes advantage of the variable permittivity of the liquid crystal, adjusted by an external electric field, providing tunable reflective phase shift of terahertz (THz) waves. We analysed the performance of this phase shifter using a simple isotropic and homogeneous model considering the angle of incidence. The phase variation was achieved in a range greater than 360° and frequencies from 349 to 361 GHz. An array constituted of 900 patch elements was fabricated using the photolithographic process. It provided tunable phase range of 350° over the frequency range of 353.5–359.3 GHz at 40 V, where a maximum phase shift 362.6° was achieved at 357 GHz. The LC dielectric constant was obtained by fitting the computed reflectance spectrum to the measured result. We compared accurate model, considering both inhomogeneity and anisotropy of the liquid crystal, with the simplified model. In addition, the differences were analysed between the measurements, accurate and conventional model. The results show the liquid crystal phase shifter is great for beam scanning antenna array in THz.

Electrically Tunable Reflective Terahertz Phase Shifter Based on Liquid Crystal

We present a reflective spatial phase shifter which operates at terahertz regime above 325 GHz. The controllable permittivity of the nematic liquid crystals was utilized to realize a tunable terahertz (THz) reflective phase shifter. The reflective characteristics of the terahertz electromagnetic waves and the liquid crystal parameters were calculated and analyzed. We provide the simulation results for the effect of the incident angle of the plane wave on the reflection. The experiment was carried out considering an array consisting of 30 × 30 patch elements, printed on a 20 × 20 mm quartz substrate with 1-mm thickness. The phase shifter provides a tunable phase range of 300° over the frequency range of 325 to 337.6 GHz. The maximum phase shift of 331° is achieved at 330 GHz. The proposed phase shifter is a potential candidate for THz applications, particularly for reconfigurable reflectarrays.

Reflective phase shifter based on wideband multi‐section hybrid coupler in slot‐coupled structure

ABSTRACTThis article presents a novel reflective phase shifter based on wideband multi‐section 3‐dB hybrid coupler in slot‐coupled structure. By terminating coupled and transmission ports of coupler with rectangular microstrip loads, reflective phase shifter is achieved. It designed on multilayer Rogers RO4003C substrate. The configuration consists of elliptically shaped transmission line and the combination of rectangular and elliptical shaped slots on the ground plane. To improve characteristics of the designed coupler especially in lower frequency band, multi‐section transmission line and altering shape of the slot on ground is proposed. By etching extra rectangular slots on the ground plane the overall size reduction is achieved. Measurement results of the proposed coupler demonstrate coupling of 3 ± 0.7 dB with 90° ± 0.6 phase shift over 1–6 GHz (143%). The novel reflective phase shifter based on the designed coupler provides phase deviation less than 0.7° on 1.2–4.8 GHz (120%). The obtained return loss is better than 10 dB as well as insertion loss is less than 1.2 dB at the frequency band of interest. © 2017 Wiley Periodicals, Inc. Microwave Opt Technol Lett 59:567–573, 2017

Проектирование микрополосковых СВЧ-фазовращателей для антенных решеток

The analysis of the features of microstrip discrete reflective phase shifters is given. The principle of forming multi-bit phase shifters based on the transmission-type phase shifter is presented. Two specific schemes are given as the implementation of the phase shifters.

Design of novel wideband reflective phase shifters with wide range of phase applications

This paper presents wideband compact differential reflective phase shifter based on the double layer slot-coupled coupler configuration. This novel phase shifter arrangement consists of a 3-dB hybrid coupler with the coupled and transmission ports terminated with rectangular and elliptically shaped microstrip loads. By altering the ports termination of the coupler, phase shifters propose differential phase ranging from −90° to +90° over 1.3–5.9GHz frequency band. To achieve different range of phase performance, the proper reactance is calculated at the outputs of coupler. These reactances are transformed to the elliptical or rectangular-shaped microstrip load with various dimensions for every phase shifter. The calculation and simulations results show that the developed circuits could provide ±30°, ±60°, ±45° and ±90° differential phase shifts. For verification of this wideband phase shifter design method, two phase shifter example with rectangular and elliptical load termination is fabricated and measured. The measured return loss of the phase shifter with elliptically load is better than 10dB over 1.3–5.9GHz frequency band as well as insertion loss is less than 1dB. The phase shift deviation is less than 2.1°. The results demonstrate that the proposed phase shifters are well suited for use in GPS/LTE/WiMax/WLAN frequency bands.

Analysis and numerical simulation of a Ku-band analog reflection phase shifter based on radio-frequency microelectromechanical varactors

The topology of a Ku-band reflection phase shifter with microelectromechanical varactors as tunable elements is presented. The phase shifter dimensions are 4 × 4.85 mm. Its calculated operating frequency is 14 GHz, the 1-dB-loss bandwidth is 700 MHz, and the phase shift over the bandwidth is no less than 145 deg.