Radio Frequency Switch Research Articles

A wideband reconfigurable filtering phase shifter based on Stub-loaded multimode resonators

Abstract In this paper, a type of reconfigurable filtering phase shifters (RFPSs) composed of stepped-impendence stub-loaded multimode resonators (SLMMR) is proposed. High frequency selectivity and wideband characteristics are realized in the presented work. Four transmission poles (TPs) are generated in the passband to exhibit a flat and wide passband. Meanwhile, the proposed SLMMR produces two controllable transmission zeros (TZs), which improves the frequency selectivity effectively. Meanwhile, radiofrequency switches are utilized to facilitate the transition between different phase shifts. Finally, the proposed RFPSs are designed and fabricated to verify the method. The measured results indicate that the designed RFPSs, which can be turned from 45° to 90° and from 135° to 180°, are capable of realizing more than 40 % FBW with a center frequency of 3.5 GHz.

High Performance CMOS RF Switch Based on Highly Carbon Doped Raised Source/Drain Regions

The demand for high-performance Radio Frequency (RF) CMOS RF SOI (Silicon on Insulator) switches has rapidly increased, driven by the need for advanced wireless technologies (1). In this paper we give new insights on high carbon incorporation, where a Si(1-y)Cy layer with 1% of substitutional carbon (y = Csub) is grown on 40 nm on top on silicon. This layer is used for Raised Source/Drain (RSD) to strain the Si channel, for reducing on-state resistivity (Ron) and which should result in a theoretical 16% gain in current (3), (4). Si(1-y)Cy growth parameters were carefully optimized to increase Csub. Firstly, with the reduction of the temperature. Then, with H2 carrier gas reduction and total pressure increase. These two process modifications have a positive impact on the carbon concentration, thanks to the higher growth rate, without layer relaxation (5).

Automatic in-situ measurement of thermal resistance for GaN HEMTs

An automatic in-situ technique for thermal resistance measurement based on an electrical method is proposed in this paper. In contrast to the conventional thermal resistance measurement circuits of the electrical method, this method involves direct measurement of the thermal resistance of GaN high-electron-mobility transistor (HEMT) devices in an operating circuit by introducing a well-matched radio-frequency switching circuit into the operating circuit. The advantage of this method is that the thermal resistance can be measured periodically on the in-situ device without changing the electrical characteristics of the device. Based on this result, the cooling curve of the HEMT device in the power amplifier (PA) circuit is collected and the thermal resistance characteristics of the HEMT are determined via the structure function method. The purpose of this paper is to successfully obtain the thermal resistance of in-situ devices through an automatic in-situ measurement circuit of thermal resistance, and to verify the feasibility of periodic detection of thermal resistance of in-situ devices.

Thermopneumatic Liquid Metal Radiofrequency Switch Actuated by Low‐Boiling‐Point Fluid

Existing radiofrequency (RF) switches used in reconfigurable antennas often encounter performance issues such as high insertion loss, low isolation, and nonlinear effects of the switch. To address these issues, this article presents a liquid metal RF switch that utilizes a heated low‐boiling‐point fluid (LBPF) to drive the movement of a eutectic gallium‐indium alloy (EGaIn) plunger to turn the switch on/off. The operating principle of the switch is to use the pressure difference generated by the liquid–vapor phase change of the LBPF to make the EGaIn plunger to contact with, or disconnect from the copper electrodes of the switch. The performances of the RF switches actuated by different LBPFs are respectively investigated, and the results show that all RF switches have millisecond response times, and the contact resistances are as low as 0.14 mΩ. In addition, good RF performances are achieved, with an insertion loss of less than 3 dB and isolation of more than 17 dB in the frequency band from 0 to 2 GHz, and no nonlinear effects. This study also validates the performance of the proposed switch for frequency reconfiguration of a folded monopole antenna.

A Review on Material Selection Benchmarking in GeTe-Based RF Phase-Change Switches for Each Layer.

The global demand for radio frequency (RF) modules and components has grown exponentially in recent decades. RF switches are the essential unit in RF front-end and reconfigurable systems leading to the rapid development of novel and advanced switch technology. Germanium telluride (GeTe), as one of the Chalcogenide phase-change materials, has been applied as an RF switch due to its low insertion loss, high isolation, fast switching speed, and low power consumption in recent years. In this review, an in-depth exploration of GeTe film characterization is presented, followed by a comparison of the device structure of directly heated and indirectly heated RF phase-change switches (RFPCSs). Focusing on the prototypical structure of indirectly heated RFPCSs as the reference, the intrinsic properties of each material layer and the rationale behind the material selection is analyzed. Furthermore, the design size of each material layer of the device and its subsequent RF performance are summarized. Finally, we cast our gaze toward the promising future prospects of RFPCS technology.

An angle of arrival estimation method for intelligent metasurface using machine learning

Today, techniques for altering electromagnetic waves and the data they transport are increasingly crucial. These techniques have become increasingly important in several communication technologies, such as intelligent metasurface, with the rise and development of next-generation wireless communication systems. Since those technologies call for locating devices, angle of arrival (AoA) analysis becomes a crucial area for research. The AoA can now be shown in various ways, and some subspace methods have already achieved great precision. However, the extensive calculation required by those techniques is one of their key shortcomings. The author developed a novel radio frequency (RF) switching circuit design in this research and applied a novel machine-learning method to signal AoA. In single-wave settings, it was discovered that the proposed machine learning method performed satisfactorily with an average difference of 0.6 degrees.

Low Energy Consumption GeTe Phase-Change Radio Frequency Switch With Direct Heating of Conductive Filament

Low Energy Consumption GeTe Phase-Change Radio Frequency Switch With Direct Heating of Conductive Filament

A broadband low‐loss SPDT RF switch using a new off‐chip compensation technology

SummaryAn off‐chip compensation technology for low‐loss and broadband characteristics of radio frequency (RF) switches is proposed based on mathematical analysis of series shunt single pole double throws switches in this letter. This compensation technology can absorb the parasitic parameters of the switch Field Effect Transistor, improving the insertion loss and return loss of the switch as well as supporting higher bandwidth. To verify the design principle, a RF switch, using the SANAN GaAs 0.15 um pseudomorphic High Electron Mobility Transistors (pHEMT) process, and an off‐chip compensation network were designed and implemented. Specifically, after using an off‐chip compensation network, the measured bandwidth of switch has been expanded from 1.1–8.8 to 0.8–11 GHz, while the input and output return loss have also improved significantly.

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.

Emerging memory electronics for non-volatile radiofrequency switching technologies

Emerging memory electronics for non-volatile radiofrequency switching technologies

An ultra-high-frequency memristor circuit model

In the context of sixth-generation (6G) wireless communications technology, advanced radio-frequency switches are required to accommodate high-frequency terahertz range and complex modulation techniques. This paper proposes a flexible charge-controlled memristor model specifically designed for ultra-high-frequency applications. It describes in detail the derivation of the behavior model of the proposed memristor circuit. The memristor circuit model is built around four inverters, two multipliers, one integrator, one adder, and one differentiator. Through PSPICE simulation, the typical hysteresis loop of the memristor is thoroughly analyzed, demonstrating its suitability for use in wireless communication systems. The model exhibits a good typical hysteresis loop that operates over a wide frequency range from 100 kHz to 20 THz, meeting the specific requirements of terahertz applications. Compared to existing memristor designs, it operates at a much higher frequency. However, the zero crossing of the typical hysteresis loop deviates when the operating frequency exceeds 20 THz. Furthermore, the proposed memristor model can be customized in terms of set/reset voltage, operating frequency and , and has been verified for use in high speed switches with switching speeds of 19.5 ps. Furthermore, this research fills the gap in ultra-high-frequency memristor modeling, offering valuable insights and guidance for the utilization of memristors in the 6G technology and ultra-high frequency fields.

Optimization of electrical properties and radio frequency applications of GeTe thin film

GeTe belongs to a chalcogenide phase change material, which can dynamically achieve reversible switching between the crystalline state of low resistivity and the amorphous state of high resistivity by utilizing the thermally induced phase change characteristics. The GeTe is an important functional material in the fields of memristors and nonvolatile radio frequency (RF) switches. For RF switch applications, this paper focuses on optimizing the electrical performance of GeTe thin films prepared by magnetron sputtering. By comprehensively analyzing the effects of substrate materials, sputtering conditions, and annealing conditions on the resistivity of crystalline GeTe films, effective conditions for preparing low resistivity GeTe films are explored. Fig. (a) shows that compared with the GeTe film on a SiO<sub>2</sub> substrate, the film on an Al<sub>2</sub>O<sub>3</sub> substrate can obtain higher crystallinity and lower resistivity. For the deposition power and pressure shown in Fig. (b), the combination of medium power (50–80 W) and low pressure (2–3 mTorr) is beneficial for low crystalline resistivity of GeTe film. Additionally, Fig. (c) shows that higher annealing temperature (350–400 ℃) can realize lower film resistivity. Finally, the experimental results show that the lowest crystalline resistivity of the prepared GeTe thin film reaches 3.6×10<sup>–6</sup> Ω·m, and the resistance ratio is more than 10<sup>6</sup>. Based on rectangular chips of GeTe film, a parallel millimeter-wave switch with zero static power is also constructed. As shown in Fig. (d), the insertion loss is less than 2.4 dB, and the isolation is greater than 19 dB in a 1–40 GHz frequency band, demonstrating the potential application of GeTe thin films in the field of broadband high-performance discrete nonvolatile RF switches.

MOSFET-Based RF Switch With Active Biasing

A biasing method for a stacked field-effect transistor (FET)-based radio-frequency (RF) switch is proposed. The advantage of the method over conventional passive resistive biasing is the ability to sustain a desirable operating point under the peak RF excitation conditions achieved by compensating the excessive leakage current of FETs in the stack. Operating point stabilization results in improved RF voltage-handling capabilities of the OFF-state switch. A single-pole double-throw (SPDT) hardware demonstrator implemented in a dedicated 130-nm bulk-CMOS RF switch technology shows an increase in breakdown voltage by 10% for a 35-V voltage-handling class switch device. The improvement is achieved at the expense of increased peak current consumption and no penalty in the RF performance of the switch.

Effect of PIN Diode Integration on Patch Antennas for Frequency Reconfigurable Antenna Applications

PIN diodes are commonly used to design reconfigurable antennas owing to their sufficient isolation, lower cost, and ease of fabrication. This study aims to explore the effect of biasing conditions of a PIN diode radio frequency (RF) switch on a frequency-reconfigurable antenna. This approach investigates the contribution of the forward diode current and the reversed biased voltage on the shift in the operating band, the impedance matching, and the radiation efficiency of a reconfigurable antenna. The benefits and drawbacks of different approaches to modeling PIN diode RF switches are demonstrated on Ansys electromagnetic switch. The result shows a significant match between simulated and measured operating bands, impedance matching, and radiation efficiency. The proposed RF switch model can be used as a practical simulation model for implementing various reconfigurable microwave components.

Nonlinear restructuring of patterned thin films by residual stress engineering into out-of-plane wavy-shaped electrostatic microactuators for high-performance radio-frequency switches

Electrostatic microelectromechanical (MEMS) switches are the basic building blocks for various radio-frequency (RF) transceivers. However, conventional cantilever-based designs of MEMS switches require a large actuation voltage, exhibit limited RF performance, and suffer from many performance tradeoffs due to their flat geometries restricted in two dimensions (2D). Here, by leveraging the residual stress in thin films, we report a novel development of three-dimensional (3D) wavy microstructures, which offer the potential to serve as high-performance RF switches. Relying on standard IC-compatible metallic materials, we devise a simple fabrication process to repeatedly manufacture out-of-plane wavy beams with controllable bending profiles and yields reaching 100%. We then demonstrate the utility of such metallic wavy beams as RF switches achieving both extremely low actuation voltage and improved RF performance owing to their unique geometry, which is tunable in three dimensions and exceeds the capabilities of current state-of-the-art flat-cantilever switches with 2D-restricted topology. As such, the wavy cantilever switch presented in this work actuates at voltages as low as 24 V while simultaneously exhibiting RF isolation and insertion loss of 20 dB and 0.75 dB, respectively, for frequencies up to 40 GHz. Wavy switch designs with 3D geometries break through the design limits set by traditional flat cantilevers and provide an additional degree of freedom or control knob in the switch design process, which could enable further optimization of switching networks used in current 5G and upcoming 6G communication scenarios.

Resistance Ratio Enhancement in Phase-Change RF Switches at Cryogenic Temperatures

This letter reports the dc and radio frequency (RF) performance of the phase-change RF switches (PCRS) as a function of temperature. Resistance change behavior of the germanium telluride (GeTe) material is experimentally investigated over 77 to 335 K. The device shows metallic behavior in the crystalline state which exhibits consistent low resistivity over a wide temperature range, while in the amorphous state, resistance increases to more than eleven orders of magnitude as a function of decreasing temperature from 300 to 77 K. Device current–voltage (IV) characteristics and the RF performance are investigated for multiple device cycles. The RF performance of the PCRS is reported with and without microheater are examined to confirm the performance variation of the phase-change switches at cryogenic temperatures.

High-speed silicon-integrated photonic radio frequency switch based on optical switching.

Photonic radio frequency (RF) switches are promising to replace conventional electronic RF switches in modern RF communication systems owing to their high switching speed and immunity to electromagnetic interference. However, existing photonic RF switches are generally based on frequency or polarization filtering. Thus, they require more light sources and filters to increase the number of switching channels, consequently limiting scalability. We propose a silicon-integrated photonic RF switch based on optical switching. RF signals are first modulated into the optical domain and switched through phase control of the phase shifters in the optical switch. Switching is not related to the frequency or polarization of the optical carriers, thus reducing the number of light sources required. Experimental results demonstrate 10-GHz switching of two RF signals with frequencies of 20 GHz and 30 GHz. The proposed photonic RF switch can be further expanded to form a large switch matrix, possibly contributing to the development of large-scale RF communication systems.

A Photonics-Assisted Binary/Quaternary Phase-Coded Microwave Signal Generator Applicable to Digital I/O Interfaces.

A photonics-assisted binary/quaternary phase-coded microwave signal generator with fundamental/doubling reconfigurable carrier frequency applicable to digital I/O interfaces is proposed and has been verified by experiments. This scheme is based on a cascade modulation scheme, which is used to reconfigure fundamental/doubling carrier frequency and load the phase-coded signal, respectively. By controlling the radio frequency (RF) switch and the bias voltages of the modulator, the switching of the fundamental or doubling carrier frequency can be realized. When the amplitudes and sequence pattern of the two independent coding signals are set reasonably, binary or quaternary phase-coded signals can be realized. The sequence pattern of coding signals is applicable to digital I/O interfaces and can be directly generated through the IO interfaces of FPGA instead of an expensive high-speed arbitrary waveform generator (AWG) or other digital-to-analog conversion (DAC) systems. A proof-of-concept experiment is carried out, and the performance of the proposed system is evaluated from the aspects of phase recovery accuracy and pulse compression capability. In addition, the influence of residual carrier suppression and polarization crosstalk in non-ideal states on phase shifting based on polarization adjustment has also been analyzed.

Research of Electromagnetic Parameters of the Radio-Frequency Micromechanical Switch Designed for Operation in 5G Transceiver Systems

This article presents the results of an experimental study of the electromagnetic parameters (scattering parameters) of a manufactured experimental sample of a capacitive single-pole single-throw radio-frequency micromechanical switch with an electrostatic activation mechanism designed to operate in the transceiver radio-modules of 5G mobile networks in the frequency range NR FR1, namely at a central resonant electrical frequency of 3,6 GHz. The effective operating frequency range of the developed and manufactured experimental sample of a radio-frequency micromechanical switch is the S-frequency range. The basis for the development of the presented experimental sample is the developed methodology for designing capacitive radio-frequency micromechanical switches with an electrostatic activation mechanism.

Four-channel all-optical wavelength conversion unit based on nonlinear effect of three-section monolithically integrated semiconductor lasers.

A simple and highly efficient four-channel all-optical wavelength conversion based on four-wave mixing effect of the directly modulated three-section monolithically integrated semiconductor laser is proposed and experimentally investigated. For this wavelength conversion unit, the spacing of the wavelength can be adjusted by tuning the bias current of the lasers and setting it to be 0.4nm (50GHz) as a demonstration is this work. A 50Mbps 16-QAM signal centers at 4-8GHz is experimentally switched to a targeted path. Up- or downconversion depends on a wavelength-selective switch, and the conversion efficiency can reach up to -2 to 0dB. This work provides a new technology for photonic radio-frequency switching matrix and contributes to the integrated implementation of satellite transponders.