Single-pole Double-throw Switch Research Articles

Miniaturized, Ultra-Wideband and High Isolation Single Pole Double Throw Switch by Using π-Type Topology in GaAs pHEMT Technology

In this brief, a compact ultra-wideband monolithic microwave integrated circuit single pole double throw (SPDT) switch with high isolation level and low insertion loss is presented. A ${\pi }$ -type topology, consisted of a transmission line with an electrical length of less than 90° and two parallel grounded metal-insulator-metal capacitors, is employed to replace the conventional $\lambda $ /4 transmission line between the adjacent parallel field effect transistors of the serial parallel SPDT switch. In comparison with the traditional method, an ultra-wideband high isolation behavior and the reduced dimension is achieved simultaneously with the proposed SPDT switch. Furthermore, the equivalent circuit model is built to interpret the mechanism of the improved technique. A chip sample is fabricated with Gallium Arsenide processing with a size of $1.25\times 1.05$ mm2. The measured insertion loss is less than 1.9 dB and the isolation is better than 36 dB from DC to 30 GHz. Good agreements are observed between the simulated and measured results.

Beam-Reconfigurable Multi-Antenna System with Beam-Combining Technology for UAV-to-Everything Communications

This paper proposes a beam-reconfigurable antenna for unmanned aerial vehicles (UAVs) with wide beam coverage by applying beam-combining technology to multiple antennas with different beam patterns. The proposed multi-antenna system consists of a circular patch antenna and a low-profile printed meandered monopole antenna. For beam combining, a coplanar waveguide with ground (CPW-G) structure feeding network is proposed, and it consists of two input ports, a 90° hybrid coupler, a microstrip 90° phase delay line, and a single-pole double-throw (SPDT) switch. It performs the role of power distribution and phase adjustment, and synthesizes the broad-side beam of the monopole antenna and the end-fire beam of the patch antenna to form the directive broadside beams in four different directions. The proposed antenna system operates at 5–5.5 GHz which covers both UAV ground control frequencies (5.03–5.09 GHz) and UAV mission frequencies (5.091–5.150 GHz). The peak gain, total efficiency, and half-power beamwidth (HPBW) of the antenna system are approximately 5.8 dBi, 76%, 145° in the elevation plane, and 360° in the azimuth plane respectively. Its electrical size and weight are λ 0 × λ 0 × 0.21 λ 0 at 5.09 GHz and 19.2 g, respectively.

A High-Power 24–40-GHz Transmit–Receive Front End for Phased Arrays in 45-nm CMOS SOI

This article presents a dual-band millimeter-wave front end in 45-nm CMOS silicon-on-insulator (SOI) for 5G applications. The front end is composed of a low-noise amplifier (LNA), power amplifier (PA), and a single-pole double-throw (SPDT) switch. A double-tuned PA is used and is based on a two-stage stacked amplifier with a reconfigurable load using SOI switches, so as to achieve an optimal load for both 28- and 39-GHz 5G NR bands. A wideband series-shunt switch is also developed with high power handling (P1dB >22 dBm) and $P_{\mathrm {sat}}$ is > 18.8 dBm and the peak PAE is 18% at 24–30 GHz and includes the switch loss and compression. For high-band operation, the gain at 36–40 GHz is 13.6 ± 1.5 dB with $P_{\mathrm {sat}} > 18$ dBm. To the best of our knowledge, this is the first front end that covers both the 24–28- and 37–40-GHz 5G bands with high output power and low-NF. Application areas are in multistandard base stations and small cells.

Switchable Filtering Circuit With Single- and Multi-Channel Operations

In this brief, we proposed a switchable filtering circuit with single- and multi-channel operations. It is a six-port circuit, consisting of three sections, namely, a switchable single- and quad-channel filtering circuit, a reconfigurable impedance matching network (IMN), and a single-pole double-throw (SPDT) switch. Two of the ports can be switched to satisfy the requirement of a time division duplexer sub-system, while other four ports can be reconfigured to transmit or receive signals in one channel or four channels. The presented switchable circuit can be utilized as the feeding network of a switchable directive and omni-directional antenna systems by using only directive antennas, while the omni-directional antenna can be eliminated. The design methods and experimental results of the presented switchable filtering circuits are given to verify the proposed ideas.

Time-Modulated Arrays With Haar Wavelets

Time-modulated arrays (TMAs) can effectively perform beamsteering over the first positive harmonic pattern by applying progressively delayed versions of stair-step approximations of a sine waveform to the antenna excitations. In this letter, we consider synthesizing such stair-step sine approximations by means of Haar wavelets. Haar functions constitute a complete orthonormal set of rectangular waveforms, which have the ability to represent a given function with a high degree of accuracy using few constituent terms. Hence, when they are applied to the TMA synthesis, employing single-pole double-throw switches, such a feature leads to an excellent rejection level of the undesired harmonics as well as a bandwidth greater than that supported by conventional TMAs with on - off switches.

Effect of Stress on Pull-in Voltage of RF MEMS SPDT Switch

RF MEMS switches are well known to exhibit performance superior to solid-state devices. However, electromechanical issues, such as repeatability and higher pull-in voltage, are a matter of concern. MEMS switches generally consist of metallic beams which curl up or down based on stresses in the structure. Stress-induced curling-up phenomenon, in such structures, increases the gap between the actuating electrode and the freely suspended metallic structure which in turn increases the pull-in voltage. This article focuses on simulations and curve fitting to analyze the effect of stress on pull-in voltage. The pull-in voltage of the switch is proportional to stress, and accordingly, its dependence on in-built stress and Young's modulus is analyzed. In addition to mechanical analysis, RF response of the single pole double throw (SPDT) switch is discussed as a case study. Measured stress and pull-in voltage of the SPDT switch is 50 MPa and 16 V. In the presence of stress, the curled-up cantilever switch shows measured isolation better than 31 dB for dc to 10-GHz range.

A Novel 5-GHz SPDT Switch Using Semiconductor Distributed Doped Areas

This letter presents a novel 5-GHz transmitter/ receiver (TX/RX) single-pole double-throw (SPDT) switch designed on a silicon substrate. The novelty of this SPDT switch is the possibility it offers to simultaneously design the transmission lines and the active elements, without packaging and consequently its parasitic effects and frequency limitations. The device is intended to be easily integrated into a system with a more complex function, e.g., with amplifiers and antennas. The codesign method offers great flexibility in the positioning and sizing of the active elements, i.e., semiconductor distributed doped areas (ScDDAs), which are integrated n+pp+ junctions, in order to obtain the best possible performances in both aspects. A demonstrator provides proof of the concept. In RX-mode, the insertion loss (IL) is 0.9 dB with isolation (ISO) higher than 30 dB. In TX-mode, IL is 2.38 dB and ISO is higher than 43 dB.

A 60-GHz SiGe Radiometer Calibration Switch Utilizing a Coupled Avalanche Noise Source

This letter presents a novel implementation of a ${V}$ -band single-pole double-throw switch that facilitates the internal calibration of radiometers by integrating an ambient noise source and an avalanche noise source. The switch is implemented in a 0.13- $\mu \text{m}$ SiGe bipolar-CMOS (BiCMOS) process and uses a shunt topology with $\lambda $ /4 directional couplers that inject noise from the avalanche source. The avalanche source is implemented using the collector-base junction of a SiGe heterojunction bipolar transistor (HBT) and attains a measured excess noise ratio of 18.7 dB at 60 GHz. The switch achieves a midband insertion loss of 2.0 dB and an isolation of 22 dB at 60 GHz. An excess input-referred noise temperature of 620 K is added with the noise source ON. To the best of our knowledge, this is the first avalanche noise source using a diode-configured SiGe HBT and the first monolithic two-reference switch for calibrating millimeter-wave radiometers.

Design and of analysis of SPDT Ohmic RF MEMS switch

This paper reports on the simulation and analysis of Ohmic SPDT (single pole double throw) switch for telecommunication application. A comparative study is performed by varying the gaps from 3 to 2 μm for three different types of beam materials, namely gold, aluminum, and platinum. The design is based on the series configuration consisting of two cantilever type switches. In order to improve isolation, low-frequency Ohmic SPDT switch is proposed. The main objective of the paper is to achieve low frequency to fit into C-band. By using COMSOL Multiphysics tool, we found pull-in-voltage as 2.8 V at a beam with 0.5 μm. The performance analysis is done by using HFSS tool and is found to perform at 7.3 GHz with isolation of − 43 dB, the return loss and insertion losses are − 21 and − 1.3 dB, respectively.

Design and analysis of a dual function of switchable resonator for RF switch

This paper presents the design and analysis of a dual function of a switchable resonator for Radio Frequency (RF) switch. The most common configuration of RF switch is Single Pole Double Throw (SPDT) switch that widely used in the wireless communication system. In order to achieve the dual function between isolation improvement and band-stop filter in SPDT switch, two switchable resonators were used that resonated at 2.3 and 5.2 GHz bands. PIN diodes were used as switching elements in the SPDT switch. The main advantages of the dual function of the switchable resonator are minimum usage of switching elements for isolation and integrated band-stop filter in a single device of SPDT switch. As a result, the design showed almost 40 dB of isolation at 2.3 GHz and 39 dB of the notch response of the band-stop filter at 5.2 GHz.

Small-signal design consideration for two-dimensional change-over switch GaN MMICs

This paper presents small-signal design consideration for two-dimensional change-over switch GaN monolithic microwave integrated circuits (MMICs). For the design of two-dimensional change-over single pole single throw (SPST) switch circuit which electrically changes between low pass filter and high pass filter, the demands for design conditions are as follows: 1. two-dimensional switch with time/frequency domain. 2. The sufficient isolation in off-state at the signal frequencies for both low band and high band. Two-dimensional change-over single pole double throw (SPDT) switch provides a duplexer for frequency division duplex operation and an SPDT switch for time division duplex operation for low-cost the fifth generation (5G) front-ends (FEs). GaN two-dimensional change-over SPST and SPDT MMIC switches are successfully demonstrated by using 0.25 μm GaN foundry process for high power handling capability in 5G FEs. The demonstrated GaN MMIC switches shows almost the same two-dimensional switching characteristics as the designed ones.

Advanced photo-induced substrate-integrated waveguides using pillar-array structures for tunable and reconfigurable THz circuits.

Substrate-integrated waveguides (SIWs) have recently attracted increasing attention for the development of terahertz (THz) circuits and systems. However, conventional SIWs employ fixed metallic vias to form the waveguide sidewalls, resulting in limited tunability and reconfigurability. In this paper, we report a novel approach for the realization of high-performance tunable and/or reconfigurable THz SIW structures. In this approach, photo-induced free carriers are generated in a high-resistivity silicon pillar-array structure to form well-defined, highly conductive, vertical sidewalls. The wave propagation properties of these optically-defined photo-induced SIWs (PI-SIWs) have been evaluated using full-wave electromagnetic simulations. Higher-functionality THz components, including a single-pole double-throw switch and a phase shifter were also designed and simulated. Based on these example circuits, PI-SIWs using pillar-array structures appear to be attractive candidates for the development of tunable and reconfigurable THz components for THz sensing, imaging, and communication systems.

Bandwidth Improvement of MMIC Single-Pole-Double-Throw Passive HEMT Switches with Radial Stubs in Impedance-Transformation Networks

In this paper, we propose a new configuration for improving the isolation bandwidth of MMIC single-pole-double-throw (SPDT) passive high-electron-mobility transistor (HEMT) switches operating at millimeter frequency range. While the conventional configuration adopted open-stub loading for compensation of the off-state capacitance, radial stubs were introduced in our approach to improve the operational bandwidth of the SPDT switch. Implemented in 0.15 m GaAs pHEMT technology, the proposed configuration exhibited a measured insertion loss of less than 2.5 dB with better than 30 dB isolation level over the frequency range from 33 GHz to 44 GHz. In terms of the bandwidth of operation, the proposed configuration achieved a fractional bandwidth of 28.5% compared to that of 12.3% for the conventional approach. Such superior bandwidth performance is mainly attributed to the less frequency dependent nature of the radial stubs.

Low-Loss Millimeter-Wave SPDT Switch MMICs in a Metamorphic HEMT Technology

This letter presents the design and performance of two single-pole double-throw (SPDT) switches operating in $V$ -band (50–75 GHz) and $W$ -band (75–110 GHz). The millimeter-wave (mmW) integrated circuits (MMICs) are fabricated in a 50-nm gate-length metamorphic high-electron-mobility transistor technology. Special attention was paid to the reduction of the insertion loss (IL). Thus, both switch MMICs achieve an IL of 1–1.6 dB (average 1.2 dB), covering the entire $V$ -band and $W$ -band, respectively. The isolation (ISO) of the switches is better than 31.6 and 28.5 dB, respectively. The input power for 1 dB of IL compression is at least 22 and 19 dBm, respectively. A wafer mapping of both circuits exhibits a high yield and low spread of IL and ISO. Based on the given results, the presented SPDT switch MMICs demonstrates state-of-the-art performance.

A Full X-Band Phased-Array Transmit/Receive Module Chip in 65-nm CMOS Technology

In this paper, we present a phased-array transceiver chip operating in full X-band (8-12 GHz) in 65-nm CMOS technology. The presented transceiver for the transmit/receive module (TRM) consists of a 6-bit passive phase shifter, a 6-bit attenuator, a bi-directional gain amplifier (BDGA), and a single pole double throw (SPDT) switch connected to the internal power amplifier (PA) and the low-noise amplifier (LNA) to serve as a duplexer. A 64-bit SPI scan-chain is integrated for digital TRM control. The transmitter achieves greater than 15 dB of power gain with 11.84 dBm at the output 1-dB compression point (OP1dB). To achieve a wideband operation of the passive phase shifter, we assigned two different resonant frequencies for the phase leading and lagging networks and aligned the slopes of their phase responses to have the desired phase shifts at the center frequency. The RMS phase error is less than 5°, and the RMS amplitude error is less than 0.45 dB for all phase and attenuation states within 8-12 GHz while dissipating 216 mW dc power from a 1 V power supply. The receiver shows greater than 15 dB of power gain and has a noise figure (NF) of less than 8.4 dB for the entire X-band. The RMS phase error and the RMS amplitude error are less than 5° and 0.45 dB, respectively, for all control states within 8-12 GHz. The receiver consumes 110 mW with a 1 V power supply. The transceiver chip occupies an area of $4\times1.88$ mm 2 .

An Integrated Switchable EM Absorber and Beam Switchable Radiator

In this research work, a multifunctional metamaterial inspired surface is designed for two different applications, namely, electromagnetic (EM) absorber and radiator with pattern agility. The designed surface consists of periodic arrays of metallic loops and circular patches printed on a thin grounded dielectric slab. Lumped resistors are fixed in the outer ring where the inner patch is connected to the feeding network through metallic vias. Firstly, the basic unit cell of the surface is utilized as a dual-band EM absorber. Secondly, the same surface is utilized as a beam switching radiator. Each unit cell has two switchable feeding points which are connected to a single-pole double-throw (SPDT) switch designed on the bottom layer. The surface is symmetrical therefore the excitation of each unit cell at two feeding ports can produce a phase shift of 180°. By properly selecting the feeding point of the four elements, the surface can generate sum-beams and difference-beams. The surface exhibit low radar cross section (RCS), high gain, and high efficiency. A prototype of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${4} \times {4}$ </tex-math></inline-formula> elements array is manufactured and experimentally verified in an anechoic chamber.

An OAM-Mode Reconfigurable Array Antenna With Polarization Agility

An Orbital angular momentum (OAM) antenna with both mode reconfigurability and polarization agility is proposed in this paper. The proposed antenna is designed based on a four-element uniform circular array with a phase-shifting reconfigurable feed network. To reduce its dimensions and complexity, the feed work is constructed with two stages of single-pole double-throw switches and a stage of 90° phase-shifting power dividers, partially of which can be shared among the chosen operating states. Moreover, the use of a small amount of p-i-n diodes as binary switches allows low insertion loss and low component cost. By varying the ON/OFF status of the diodes strategically, the resultant array can be reconfigured to horizontal polarization (HP) or vertical polarization (VP), along with OAM mode $l = -1$ or +1 achieved for each polarization. The antenna performance is evaluated in terms of reflection coefficients, near-field distributions and far field radiation patterns. According to the measured results, the antenna exhibits an overlapped frequency band ranging from 2.29 to 2.59 GHz among the different operating states. Meanwhile, stable radiation patterns as well as high cross-polarization discrimination can be obtained. Benefiting from the above features, the antenna could help to improve the signal quality and increase the channel capacity in wireless communications.

Reconfigurable Filter for Bandpass-to-Absorptive Bandstop Responses

A frequency tunable filter with a bandpass-to-absorptive bandstop reconfigurable characteristic is studied, designed and validated theoretically and experimentally. To control the filter bandwidth and impedance matching performance, variable capacitors are used in each external and internal coupling structure, and, by using equivalent circuits, the required frequency responses of two different modes are obtained. Two single-pole double-throw switches embedded in the transmission lines running from the source to the load accommodate external coupling structures to control the operational mode of the proposed filter. All commercially available electronics such as switches and varactor diodes are placed on the microstrip line layer, and the frequency-tunable substrate integrated waveguide (SIW) resonators are coupled to the transmission line through coupling slots. In the absorptive bandstop mode, the stopband is tuned from 1.83 GHz to 2.49 GHz, while the passband can be tuned from 1.86 GHz to 3.3 GHz in the bandpass mode. In both modes, more than 10 dB in return loss over the frequency tuning range of interest has been achieved. Theoretical, simulated, and measured results are in good agreement, which validate the proposed filter structure.

Single-/Dual-Band Bandpass Filter-Integrated Single-Pole Double-Throw Switch Using Distributed Coupling Tri-Mode Resonators

This article presents a method to design a single-band (SB)/dual-band (DB) bandpass filter (BPF)-integrated single-pole double-throw (SPDT) switch by using one/two distributed coupling identical tri-mode resonator (TMR) pairs loaded with opposite polarity p-i-n diodes. Moreover, the proposed method is also directly suitable for designing the multiple-band (MB) BPF-integrated SPDT switch by simply increasing the used numbers of identical TMR pairs. As an example, a SB-BPF-integrated SPDT switch with the central frequency (CF) of 1 GHz and the ripple bandwidth (RBW) of 65 MHz is first designed by using one identical switchable TMR pair, so as to validate our design approach. Due to the inherent property of TMR and the introduced source–load coupling, high ON-state passband selectivity is achieved. Then, two switched 50- $\Omega $ matching circuits are connected to two noncommon feeding lines, and an SB-BPF-integrated SPDT switch with absorptive OFF-state property is also realized. Finally, a DB-BPF-integrated SPDT switch with CFs of 0.9 GHz/1.8 GHz and RBWs of 50 MHz/105 MHz is designed by simply employing two identical TMR pairs. When the operating states of two identical switchable TMR pairs are specifically chosen, the proposed DB-BPF-integrated SPDT switch exhibits multiple functions, i.e., the 900/1800 SB-BPF-integrated SPDT switches with absorptive OFF-state property, the 900/1800 DB-BPF-integrated SPDT switch with absorptive OFF-state property, and the 900/1800 diplexer-integrated SPDT switch. The measured results also show that these switches exhibit low ON-state passband losses, deep out-of-band rejections (OBRs) of ON-state passbands, high OFF-state suppressions (OSSs), high port-to-port isolations (PPIs), and compact circuit sizes.

BPF-Integrated SPDT Switches With Improved Performance Using Frequency Selective Star-Junction Matching Circuit and Switched Magnetic Coupling Technique

This article presents a type of bandpass filter (BPF)-integrated single-pole double-throw (SPDT) switch using the frequency selective star-junction matching circuit and the switched magnetic coupling (SMC) technique, i.e., the lowpass phase shifter (LP-PS) and the quasi-elliptic lowpass filter (QE-LPF) with specified phase shift. Firstly, a high selectivity third-order BPF-integrated single-pole single-throw (SPST) switch with cross coupling and mixed electric and magnetic coupling (MEMC) is designed by the classical coupled-resonator filter design theory. A 34-dB OFF-state suppression (OSS) is achieved due to the detuned resonators, and the OSS can be further increased to 60 dB by the introduced SMC. Then, the BPF-integrated SPDT switches are designed by using proposed frequency selective star-junction matching circuit to cascade the above designed BPF-integrated SPST switch with or without SMC. The proposed frequency selective star-junction matching circuit is used to not only provide the required phase shift for meeting the impedance matching condition, but also have lowpass frequency response for expanding the upper stopband of ON-state channel, the rejection bandwidth of OFF-state channel, and the port-to-port isolation bandwidth. As examples, four BPF-integrated SPDT switches are designed and fabricated to validate the proposed design approaches, which show the improved electrical performance.