6-bit Phase Shifter Research Articles

An 8~18 GHz 6-bit phase shifter with balance-compensated balun

An 8~18 GHz 6-bit phase shifter with balance-compensated balun

Design of 2.5-3.3 GHz high-precision compact digital phase shifter

Abstract A 6-bit MMIC digital phase shifter, designed using a 0.5 μm GaAs pHEMT process, has been developed to enhance the search capability of phased array systems for targets. The chip structure of the phase shifter is well-designed, and the improved embedded topology of the 45° and 90° phase shifting units effectively reduces the overall insertion loss. To reduce the chip size, the phase shifting units with smaller layouts of 5.625°, 11.25°, and 22.5° are combined, greatly reducing the chip area. The results show that within the frequency range of 2.5-3.3 GHz, the input and output VSWR is less than 1.38, the insertion loss is less than 4.3 dB, the root mean square phase error of the phase shifting state is less than 1.43°, and the absolute value of the amplitude fluctuation for different states is less than 0.52 dB. The compact chip structure measures 2.45 mm×1.08 mm.

Complementary split resonant ring inspired wide-angle frequency-scanning patch array leaky-wave antenna with open-stopband suppression

In this paper, a wide-angle scanning and dual-linearly polarized leaky-wave antenna (LWA) is proposed based on symmetrical complementary split resonant ring (CSRR) feeding lines. The CSRR excites high-dispersed spoof surface plasmon polaritons (SSPPs) and is inspired to enlarge the scanning angle of the circular patch array antenna. The coupling between CSRR and circular patch determines the unit cell dispersion characteristics of LWA, and the coupling between CSRR and circular patch is controlled by designing their respective periods, p/b, to suppress the open-stopband and reduce the grating lobe, The value of p/b controls the frequency range of the open-stopband. Two parallel CSRR feeding lines are located on the bottom layer of the antenna and feed the array antenna of 11 circular patches above the feeding layer with both differential and common modes excitations. The two modes switch with 1-bit phase shifters on the two parallel feeding lines fed with a Wilkinson power splitter and electronically switch dual-linearly polarized radiations. The proposed scenario of the LWA prototype is validated through simulations and experiments. According to the measurements, horizontally polarized radiation achieves large beam scanning angle from −59.5° to +40° in the frequency range from 8 to 11 GHz with common mode excitation. And vertically polarized radiation scanning the main beam from −47° to +41° in the frequency range from 7.8 to 10.8 GHz with differential-mode excitation. The measured peak gains of the two polarizations are 14.4 dBi and 14.2 dBi, respectively, and the cross-polarization ratios are above 21 dB.

A novel 6.5-13.5GHz 6-bit digital phase shifter with ultra low RMS phase error in 0.25-µm GaAs p-HEMT technology

A novel 6.5-13.5GHz 6-bit digital phase shifter with ultra low RMS phase error in 0.25-µm GaAs p-HEMT technology

Dual-band dual-polarized sub-6 GHz phased array antenna with suppressed higher order modes

This manuscript proposes a dual-band dual-polarized 64-element phased array antenna (PAA) with suppressed higher order modes (HoMs). Each array element is a microstrip patch structure with complementary split ring resonator (CSRR) loading, allowing for simultaneous dual-band and dual-polarization performance at 3.45 GHz and 3.87 GHz. The proposed PAA exhibits impedance matching of ≤-20\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\le - 20$$\\end{document} dB at 3.45 GHz and 3.87 GHz while limiting the mutual coupling below -19\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$- 19$$\\end{document} dB between the adjacent elements at both the operating bands. The proposed design includes a plated through hole placed near the CSRR loading to suppress any higher-order modes (HOMs). Two antenna prototypes, without and with HOMs suppression techniques are fabricated and measured. In addition, we demonstrate the beam steering of the proposed PAA up to ±600\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\pm 60^0$$\\end{document} using an off-the-shelf 6-bit phase shifter module. The proposed 64 -element array achieves a gain of 23 dBi, and shows a minimal steering loss of ≃3\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\simeq 3$$\\end{document} dB over the steering angle.

Wideband Single-Sideband Time Modulator Based on Practical 2-bit Switched-Type Phase Shifter

Wideband Single-Sideband Time Modulator Based on Practical 2-bit Switched-Type Phase Shifter

A 28 GHz GaN 6-Bit Phase Shifter MMIC with Continuous Tuning Calibration Technique.

A 28 GHz digitally controlled 6-bit phase shifter with a precision calibration technique in GaN high-electron mobility transistor (HEMT) technology is presented for Ka-band phased-array systems and applications. It comprises six stages, in which stages 1 and 2 for 5.625° and 11.25° are designed in the form of a switched-line circuit, and stages 3, 4, and 5 for 22.5°, 45°, and 90° are designed in the form of a switched-filter circuit. The final stage 6 for 180° is designed in a single-to-differential balun followed by a single-pole double-throw (SPDT) switch for achieving an efficient phase inversion. A novel continuous tuning calibration technique is proposed to improve the phase accuracy. It controls the gate bias voltage of off-state HEMTs at the stage 6 SPDT switch for fine calibration of the output phase. Fabricated in a 0.15 μm GaN HEMT process using a die size of 1.75 mm2, the circuit produces 64 phase states at 28 GHz with a 5.625° step. The experimental results show that the Root-Mean-Square (RMS) phase error is significantly improved from 8.56° before calibration to 1.08° after calibration. It is also found that the calibration does not induce significant changes for other performances such as the insertion loss, RMS amplitude error, and input-referred P1dB. This work successfully demonstrates that the GaN technology can be applied to millimeter-wave high-power phased-array transceiver systems.

Design and validation of scalable reconfigurable intelligent surfaces

In this paper, we share our experience in designing, prototyping, and empirically characterizing RF Switch-based Reconfigurable Intelligent Surfaces (RIS). Our RIS design consists of arrays of patch antennas, delay lines, and programmable radio-frequency (RF) switches, enabling 3D beamforming passively, without active RF components. Our design introduces two key innovations: (i) a modular structure that provides scalability for sustainable deployments, and (ii) the support for 3-bit phase shifters, enabling high-spatial resolution codebooks. We realized this design through PCB technology and affordable electronic components, then rigorously validated our prototype in a controlled setting. With this paper, we make a comprehensive characterization of our RIS publicly available via a large dataset, to promote further empirical-driven research on this topic. Finally, we present a cost analysis of our design, which underscores the importance of sustainable practices in shaping the future of wireless technologies.

A 37-40 GHz 6-Bits Switched-Filter Phase Shifter Using 150 nm GaN HEMT.

In this paper, we present a 6-bit phase shifter designed and fabricated using the 150 nm GaN HEMT process. The designed phase shifter operates within the n260 (37~40 GHz) band, as specified in the 5G NR standard, and employs the structure of a switched-filter phase shifter. By serially connecting six single-bit phase shifters, ranging from 180° to 5.625°, the designed phase shifter achieves a phase range of 360°. The fabricated phase shifter exhibits a minimum insertion loss of 5 dB and an RMS phase error of less than 5.36° within the 37 to 40 GHz. This phase shifter is intended for seamless integration with high-power RF circuits.

Design Technique of K-Band CMOS Phase Shifter with L-C-L T-Type Low Pass Structure

In this study, we designed a 5-bit K-band CMOS switch type phase shifter. In order to minimize phase and gain errors, a design technique for bits constituting the phase shifter was proposed. The proposed design technique has been achieved by adjusting the resonant frequencies of inductance and capacitance in the L-C-L T-type low pass filter structure. Through this, a method of optimizing the phase shifter with the T-type low pass filter structure was presented. The K-band 5-bit phase shifter was designed with a 65 nm CMOS process to verify the feasibility of the proposed design technique. The core size was 0.78 × 0.21 mm2. At the frequency ranges of 22.0 to 23.0 GHz, the insertion loss and RMS phase and gain errors were measured to be 7.44 ± 2.0 dB, 2.6°, and 1.2 dB, respectively.

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.

Security Enhancement for Coupled Phase-Shift STAR-RIS Networks

The secure transmission of the simultaneously transmitting and reflecting reconfigurable intelligent surface (STAR-RIS) aided communication system is investigated. Considering the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">coupled</i> phase shifts of STAR-RISs and the fair secrecy requirement of users, a new secure beamforming design is proposed for addressing the unique <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">full-space</i> mutual eavesdropping in STAR-RIS aided communications. In particular, a penalty-based secrecy beamforming algorithm is proposed to solve the resulting non-convex optimization problem, where closed-form solutions of the coupled phase-shift coefficients are obtained in each iteration. Numerical results demonstrate that 1) the proposed scheme achieves higher secrecy capacity than conventional RIS; 2) 4-bit discrete phase shifters are sufficient for secrecy guarantee.

A Wideband 1-bit Reconfigurable Electromagnetic Surface for Monopulse Radar Applications

We present a wideband 1-bit reconfigurable electromagnetic surface (REMS) for monopulse radar applications at X-band. The proposed REMS element integrates a 1-bit reflection-type phase shifter controlled by a PIN diode. By altering the working states of the PIN diode, well-defined beam scanning is obtained. Furthermore, selecting different feeding states can realize the sum (Σ) and difference (Δ) patterns. The key design issues, including element modeling, coding design, and feed optimization, are studied to obtain good Σ and Δ beam performance. Experimental results show that REMS achieves a high gain of 23.3 dBi, a low sidelobe level of -15 dB, and a low null depth of -30 dB. The wide-angle monopulse beam-scanning up to ±60° is obtained. The gain bandwidth of -3 dB ranges from 9.35 to 11.75 GHz, with a relative bandwidth of 22.75%. Thus, the proposed multi-feed REMS brings new freedom for the Σ and Δ beam scanning, which provides wide application prospects for the monopulse radar system.

Auto-Tracking Wireless Power Transfer System With Focused-Beam Phased Array

This article used image recognition and beam forming technology to build a phased array with target tracking and transmitting the microwaves with a focused beam. The coordinate position of the target is obtained from the image recognition module and converted into phase information for the phased array. This system was constructed by a 1 <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> 4 5.764-GHz phased array with four 4-bit phase shifters. The phase shifters created a focused beam, which requires not only the target’s direction angle but also the transmission distance. The target position as well as direction and distance information were gathered using image recognition. The tracking beam method was evaluated by simulation and actual measurement. The results showed that the focused beam can always be formed in real time to track the target. The transfer efficiency of the focused beam was improved higher than that of uniform phase beam within a distance of 50 cm. The automatic tracking power transmission system has a response time of about 100 ms.

A Four-Channel Bidirectional D-Band Phased-Array Transceiver for 200 Gb/s 6G Wireless Communications in a 130-nm BiCMOS Technology

This article demonstrates a fully integrated broadband four-channel phased array transceiver, capable of wireless data rates up to 200 Gb/s covering the entire <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$D$</tex-math> </inline-formula> -band (110–170 GHz). The circuit is developed in a 130-nm SiGe BiCMOS technology, featuring ft/ fmax of 300/500 GHz, and includes localized back-side etching-based ON-chip patch antennas. In both transmit and receive modes, direct up-and down-conversions are performed by in-phase and quadrature mixers driven by a multiplier-by-four local oscillator chain. A bidirectional true time delay circuit, with a resolution of 0.446 ps, which is equivalent to the accuracy of a 4-bit phase shifter, provides the squint-free beam-steering capability. Beam-steering measurements show how the beam can be steered from <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> 45 <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 45 <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> in a 7 <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> step. The transceiver achieves a 3-dB baseband bandwidth of 30 and 27 GHz in the transmit and receive modes, respectively. A wireless link demonstration is performed by mounting two chips on printed circuit boards, one in the transmit and one in the receive mode, together with plastic lenses on both sides, at a distance of 15 cm. Hardware-in-the-loop measurements show record data rates of 180 Gb/s with EVM of 12.2% using 16-QAM and 200 Gb/s with 8.3% EVM using 32-QAM. The four-channel transceiver consumes 1.95 and 2.5 W in the receive and transmit modes, respectively, which correspond to power efficiencies of 9.75 pJ/bit in the receiver mode and 12.5 pJ/bit in the transmitter mode.

2-Bit Wideband Electronically Controlled Reconfigurable Phased Array With Wide-Angle Beam-Scanning Capacity

In this paper, a 2-bit wideband electronically-controlled reconfigurable phased array with wide-angle beam-scanning capacity is proposed. Based on the current reversal mechanism and real-time delay design, a wideband 2-bit phase shifter is designed by cascading a wideband 180° phase shifter and a wideband 90° phase shifter. Then, a wideband 2-bit element is established by connecting the radiation area of the Vivaldi structure at the slot line of the phase shifter, and a metasurface slab with H-shaped metal layer is introduced to improve the scanning performance. Further, a planar wideband reconfigurable 2-bit array at 17 GHz has been designed and fabricated based on this element, and a stripline-based 1:16 power divider with the phase-shifting function is designed to simulate the space-fed spherical wave to avoid high sidelobe. Measured and simulated results are in good agreement. The measured results indicate that the main beam of the array can scan from -73° to 73° at 17 GHz by appropriately controlling the state of PIN diodes, and the gain fluctuation is only 2.18 dB. The measured 3-dB gain bandwidth of the array in the broadside direction is about 29.1% (from 14.7 GHz to 19.7 GHz). The wide-angle scanning and wideband performances are verified.

Phase and Polarization Digitally Modulated Array Using Reconfigurable DR Element: Proposal, Design, and Verification

The proposal, design, and verification of a phase and polarization digitally reconfigurable / modulated array using the reconfigurable dielectric resonator (DR) elements are developed in this paper. Different from the conventional phased arrays and reconfigurable antennas, the radiated electromagnetic (EM) wave can be flexibly controlled by simultaneously modulating its phase and polarization. To realize phase switching, a clever 1-bit phase shifter (0° / 180°) is introduced in the element design. The polarization states are controlled by integrating the switch-loaded feeding structure. And a compact 2-bit polarization tuner (0°-LP, 90°-LP, RHCP, and LHCP) is finally realized. Since every element can realize 1-bit phase and 2-bit polarization switching, the far-field beams and polarization types of the array format can be arbitrarily modulated by designing the coding sequence. To verify the proposed working principle, a compact reconfigurable metasurface-loaded DR element, and a four-element digitally reconfigurable linear array are implemented, respectively. The overlapped -10 dB impedance and 3 dB axial ratio bandwidths are 2.35-2.55 GHz (12.5 %) and 2.42-2.48 GHz (2.4 %), respectively (Covering 2.40 GHz WIFI / BT band). More importantly, it can achieve 16 different beam & polarization modes. The proposed antennas exhibit a low-cost, compact size, good bandwidth, and flexible radiation modulation capacity. They are promising candidates for future smart antennas to manipulate and control electromagnetic (EM) waves.

Pilot Optimization and Channel Estimation for Two-Way Relaying Network Aided by IRS With Finite Discrete Phase Shifters

In this paper, we investigate the problem of pilot optimization and channel estimation of two-way relaying network (TWRN) aided by an intelligent reflecting surface (IRS) with finite discrete phase shifters. In a TWRN, there exists a challenging problem that the two cascading channels from User1-to-IRS-to-relay and User2-to-IRS-to-relay and two direct channels from User1-to-relay and User2-to-relay interfere with each other. Via smartly designing the initial phase shifts of IRS and pilot pattern, the two cascading channels are separated over only four pilot sequences by using simple arithmetic operations like addition and subtraction. Then, the least-squares estimator is adopted to estimate the two cascading channels and two direct channels. The corresponding sum mean square errors (MSE) of channel estimators are derived. By minimizing Sum-MSE, the optimal phase shift matrix of IRS is proved. Then, two special matrices Hadamard and discrete Fourier transform (DFT) matrix are shown to be two optimal training matrices for IRS. Furthermore, the IRS with discrete finite phase shifters is taken into account. The Hadamard matrix requires only one-bit phase shifters to achieve the optimal Sum-MSE performance for specific numbers of IRS elements. Using theoretical derivation and numerical simulations, we find that 3 or 4-bit phase shifters are sufficient for IRS to achieve a negligible MSE performance loss for any number.

On the Use of Metal-Only Polarization Rotation Elements for Reflectarray Designs

A reflectarray antenna employing metal-only polarization rotation elements is proposed in this letter. The element is composed of double metallic layers separated by an air gap and rotates the reflection wave polarization orthogonally with respect to that of the incidence wave. By tuning the structural dimension, a pair of elements with 90° phase difference are obtained. These two elements together with their mirroring images can be employed as a 2-bit phase shifter with 0°, 90°, 180°, and 270° phase shift from 9 to 10.8 GHz. For proof-of-concept, a metal-only reflectarray containing 225 unit-cells is developed and tested. According to experimental results, the 1 dB and 3 dB gain bandwidth of the metal-only reflectarray are 19% and 38% respectively while the peak aperture efficiency is 34%. These encouraging features demonstrate that reflectarrays can be successfully designed with metal-only polarization rotation elements and present a good potential for space applications.

A 5–6-GHz CMOS Beamforming Transceiver Front-End for Fiber-to-the-Room All-Optical Wi-Fi Solution

This letter presents a 5–6-GHz CMOS beamforming transceiver front-end with high linearity and low power consumption for fiber-to-the-room (FTTR) all-optical Wi-Fi solution, which can greatly reduce the transmission power and eliminate signal mutual interference among access points compared with traditional architecture, by aggregating beams of multichannel. The transmitter (TX) employs a high-linearity power amplifier, a variable-gain amplifier, a 5-bit passive attenuator (ATT), and a 4-bit passive phase shifter (PS). The receiver (RX) is composed of a single-to-differential variable gain low-noise amplifier (LNA), frequency-tuning buffers, a 5-bit ATT, and a 4-bit PS. Implemented in a 55-nm CMOS technology, the measured output power 1dB compression point (OP1dB) of TX is better than 12.1 dBm. The error vector magnitudes (EVMs) of the TX at 0-dBm output power with 80-MHz 256-quadrature amplitude modulation (QAM) orthogonal frequency division multiplexing (OFDM) signal are better than −36.3 dB, and the EVMs of the RX at −40 dBm input power are better than −37.8 dB. The noise figure is 4.3 dB in high-gain mode.