Single-pole Single-throw Switch Research Articles

Improved Design of Ohmic RF MEMS Switch for Reduced Fabrication Steps

RF MEMS ohmic switches are prone to stiction and contact degradation. In literature, bumps are made at the contact area to reduce stiction with additional fabrication steps. In this article, ohmic switch based on cantilever configuration is developed without using any additional step. The switch structure is modified to improve its mechanical parameters, such as pull-in voltage and switching speed. The measured switching time of the switch is $1.8~\mu \text{s}$ . A footprint of the developed single pole single throw (SPST) switch is 0.9 mm2. The insertion loss and isolation of the SPST switch are better than 0.8 and 20 dB, respectively. The switch has a wide bandwidth of 10 GHz (dc to 10 GHz). The switch has completed 725 million hot cycles at 1-dBm power.

Time-modulated array beamforming with periodic stair-step pulses

Time-modulated arrays (TMAs) are able to improve the side-lobe level of the radiation pattern at the fundamental mode but cannot steer the beam at such a mode towards a given direction. Beam-steering is possible in a TMA, but only at the harmonic patterns and at the expense of a severe TMA efficiency reduction. In this work we propose a TMA approach that simultaneously performs both features over the same beam by using two sets of switches: (1) single-pole four-throw switches to generate periodic stair-step pulses suitable for efficiently synthesizing a uniform steerable beam over the first positive harmonic, and (2) single-pole single-throw switches to reconfigure the side-lobe level of the previous beam. Performance, small size, cost-effectiveness, and performance invariability with the carrier frequency are features that make this TMA approach a competitive solution for analog beamforming. Accordingly, the structure is an attractive proposal for the design of multibeam transceivers.

Integrated Actuation of Microfluidically Reconfigurable mm-Wave SPST Switches

This article demonstrates the design and performance of a single-pole single-throw (SPST) microfluidically reconfigurable switch. The switch is formed by placing a microfluidic channel over a microstrip line gap discontinuity. A selectively metallized plate located inside the microfluidic channel is repositioned with fluid flow to capacitively load the discontinuity to achieve the RF switching functionality. Different from prior works based on external micropumps, the SPST switch is integrated with a piezoelectric actuator. The switch layout is optimized to obtain a low actuation time. A switch prototype is characterized to exhibit low insertion loss (0.42 dB) at 30 GHz and wide bandwidth (18 GHz). It operates with rise and fall times down to 1.12 ms. It is actuated by three million switching cycles with no performance degradation. To the best of our knowledge, the presented switch exhibits the lowest reconfiguration time, highest operation frequency, and the highest reliability among the microfluidically reconfigurable devices reported in recent literature.

An RF-MEMS-Based Digitally Tunable SIW Filter in X-Band for Communication Satellite Applications

This paper presents a digitally tunable SIW (substrate integrated waveguide) filter designed for X-band, based on RF-MEMS (radio frequency micro-electrical-mechanical systems) technology. Four commercial off-the-shelf RF-MEMS single-pole single-throw (SPST) switches were directly mounted on the upper surface of the filter, with metallic tuning posts specifically located within each cavity to define the potential achievable frequency range. Fabricated on standard alumina substrate, the design of the filter and the biasing network enabled fine digital frequency control of up to four functional states by the inclusion of wire bondings between each switch and the substrate. A relative tuning range of 2.3% was achieved between the lower and upper discrete states of 2.76% and 2.89% in the 3 dB fractional bandwidths.

A 7.5–9 GHz GaAs Two-Channel Multi-Function Chip

Based on the 0.5 μm GaAs enhancement/depletion (E/D) Pseudomorphic High Electron Mobility Transistor (pHEMT) process, a 7.5–9 GHz two-channel amplitude phase control multi-function chip (MFC) was developed successfully. The chip was integrated with a 6-bit digital phase shifter, a 6-bit digital attenuator, and a single pole single throw (SPST) switch in each channel. A design for the absorptive SPST switch is deployed to optimize the return loss and control channel array calibration. In the 8 dB and 16 dB attenuation bit, a switched-path-type topology is employed in order to obtain a good flatness of attenuation characteristic and achieve low additive phase shift. A 27-bit serial-to-parallel converter (SPC) was introduced to decrease the control lines and pads of the chip, and the power consumption was less than 70 mW. The measurement result shows that the insertion loss is less than −13 dB and the return loss is better than −19 dB. In both channels, the 64-state root mean square (RMS) errors of the phase shifter is less than 2° and the RMS parasitic amplitude error is less than 0.2 dB. The RMS attenuation error is less than 0.45 dB and the RMS parasitic phase error is less than 2.4°. The size of the chip is 3.5 mm × 4.5 mm.

Design and optimization of a novel high isolation low insertion loss RF MEMS single-pole double-throw switch

This paper designs an RF MEMS single-pole single-throw and single-pole double-throw switch based on the Ka-band on the CPW. The electrodes of the switch are sandwiched by two dielectric layers. Each SPDT switch has a resonant frequency of approximately 35 GHz and a bandwidth of 20 GHz with an isolation greater than -38 dB and an insertion loss less than -0.8 dB. By changing the state of the SPDT switch, one is in the up state and the other is in the down state, it can achieve the function of switching on and off. The SPDT switch also operates at around 35 GHz with a return loss greater than -23 dB, an insertion loss of less than -1 dB, and an isolation greater than -38 dB.

A 300-GHz SPST Switch With a New Coupled-Line Topology in 65-nm CMOS Technology

A single-pole single-throw (SPST) switch operating around 300 GHz has been developed in this letter based on a 65-nm CMOS technology. The SPST switch adopts a novel coupled-line topology, in which MOSFETs are employed as a variable impedance component at the through- and coupled-ports to achieve a large isolation. Over the measured frequency band of 220–320 GHz, a minimum insertion loss of 3.9 dB (at 303 GHz) and a maximum isolation of 66 dB (at 250 GHz) were obtained. This achieved peak isolation is the largest value obtained so far beyond 100 GHz with a CMOS switch. An isolation larger than 39 dB was maintained for the entire frequency band measured. The measured return loss showed a maximum value of 29 dB at 312 GHz.

Best Practices for Using Electrostatic Discharge Protection Techniques for Single-Event Transient Mitigation

We provide “best practices” for single-event transient (SET) mitigation using electrostatic discharge (ESD) protection techniques. We investigate the correlation between SET suppression and RF performance when ESD protection circuits for SET mitigation are combined with various RF switches. The three different single-pole single-throw (SPST) switch configurations (conventional design, floating body, and floating body/n-well) were implemented to provide insight on how to best apply dc ESD protection techniques for also achieving robust SET mitigation. Based on two-photon absorption laser experiments and RF measurements, a conventional SPST switch configuration shows relatively poor RF performance but is effective for SET mitigation due to the SET discharge current path provided by ESD protection circuit. On the other hand, the combination of the SPST switch and the ESD circuit, which exhibits the best RF performance among the three configurations, is relatively vulnerable to SETs. Based on these results, strategies and methodologies for ESD protection techniques to effectively mitigate SET are proposed.

Programmable Coding Acoustic Topological Insulator.

Topological acoustics has recently revolutionized fundamental concepts of acoustic propagation, giving rise to strikingly unique acoustic edge modes immune to backscattering. Despite the rapid progress in this field, simultaneous realization of reconfigurability, intelligentization, and automatic control over acoustic propagation paths is posing a great challenge. This challenge is overcome by proposing the concept of a programmable acoustic topological insulator based on two digital elements "0" or "1," which consist of honeycomb-lattice sonic crystals made of cylindrical rods with different diameters. The acoustic propagation paths in the topological insulators can be controlled automatically by programming different coding sequences, which arises from efficient transformation of pseudospin-dependent edge modes on both interfaces of the digital elements. More importantly, a unique unit is experimentally fabricated that has either a "0" or "1" response automatically manipulated by an air cylinder, and design topological insulators with programmable functionality, to realize three digital acoustic devices, such as a single-pole double-throw switch, a single-pole single-throw switch, and a tunable logic gate. The proposed programmable topological insulators may enable future intelligent acoustic devices with exciting reconfigurable and programmable functionalities, which may lead to important advances in various applications, such as integrated acoustics, acoustic security, and information processing.

A Quasi-Absorptive Microwave Resonant Plasma Switch for High-Power Applications

In this paper, a new plasma-based high-power microwave single-pole single-throw (SPST) switch is introduced and experimentally investigated. This switch is composed of a two-pole evanescent-mode cavity structure loaded with two gas discharge tubes over its posts. Since part of the energy required for the tubes ignition is supplied by the incoming electromagnetic waves, the switching mechanism is quasi absorptive. A prototype SPST switch at the frequency range of 2.8–3.9 GHz is fabricated and successfully examined over the power range of 2–20 W. With less than 1 dB of insertion loss, the ON/OFF isolation varies from 13 to 22 dB, depending on the input power. The measured switching time was on the order of tens of nanoseconds, and the input third-order intercept point that characterizes linearity was +53 dBm. Upon ignition, the microwave-sustained plasma in the switch operates in the $\alpha $ -discharge regime, ensuring that the switch performance is quite stable, with no degradation after long periods of operation.

III–V super-lattice SPST/SPMT pin switches for THz communication: theoretical reliability and experimental feasibility studies

A physics-based Quantum-Modified CLassical Drift–Diffusion (QMCLDD) non-linear mathematical model has been developed for design and characterisation of GaN/AlGaN asymmetrical superlattice pin based single-pole single-throw (SPST) and single-pole multi-throw (SPMT) switches for sub-MM wave communication systems. The simulator has incorporated several important physical phenomena that arise in superlattice structure, including quantum confinement effects, generation-recombination and tunnelling generation of carriers as well as scattering limited carrier mobility and velocity in GaN/AlGaN structure. In order to reduce the dislocation density and in turn the series resistance in GaN/AlGaN heterostructure, thin AlN nucleation layer and a buffer layer are considered in the simulation. It is observed that the RF series resistance of the pin device, operating around 0.2 THz frequency regime, reduces in case of proposed superlattice structure. The advantages of super-lattice pin diode over the conventional Si devices are the faster reverse recovery time (~ 9 vs 35 ns) and lowering of forward RF series resistances (0.39 vs 1.20 Ω). This study also reveals that SPST and SPMT switches made up with super-lattice devices are characterized by low insertion loss (~ 0.13 and 0.15 dB, respectively) and high isolation (~ 65.4 and 82.5 dB, respectively). A good agreement between theory and experiment establishes the superiority of the present model over the others. A comparative analysis of Si and GaN/AlGaN super-lattice pin SPST and SPMT switches establishes the potential of the later for its application in high-frequency THz-communication. In addition to this, a detailed thermal modelling of the device has also been done to make the analysis more realistic. The junction temperature of the designed GaN/AlGaN superlattice pin switch will be as high as 377 K, which is quite moderate compared to its flat profile counterpart. To the best of authors’ knowledge, this is the first ever report on QMCLDD non-linear modelling of pin SPST and SPMT switches (series-shunt combination) at THz-arena.

Sequentially multiplexed amperometry for electrochemical biosensors

Multiplexed electrochemical biosensors are intriguing due to their capability to permit high-throughput and low-cost assays. While commercial single-chip potentiostats are one promising approach for rapidly prototyping portable and low-cost electrochemical biosensors, it is still challenging to utilize them to achieve parallel multiplexing due to the limited resources integrated onto the chips. In this paper, we provide a methodology for incorporating multiplexing into commercial single-chip potentiostats by using a sequential architecture. In the sequential architecture, the multiplexed biosensors are interfaced to the single-chip potentiostat via single-pole single-throw switches, and the measurements alternate across the sensors. We build analytical and finite element models to investigate the behavior of the sensors, particularly when they are disconnected from the potentiostat, and find that we can take advantage of the dynamics of the sensors to achieve improved sensitivity over conventional chronoamperometry. We also investigate and compare different strategies to interface the multiplexed sensors to the single-chip potentiostat. Using the proposed multiplexing architecture, we demonstrate the implementation of 16-fold multiplexed amperometry, which is validated using ferricyanide measurement. Finally, the sequential multiplexing methodology is applied to a multiplexed bead-based electronic enzyme-linked immunosorbent assays of human interleukin-6.

Single-Pole Single-Throw Switch for Substrate-Integrated Waveguide

A novel concept of a simple single-pole single-throw switch implementation for a substrate-integrated waveguide is presented in this letter. The switch design is an adaptation from the antenna theory where a resonant slot on a rectangular waveguide, inclined with respect to the line axis, realizes a series impedance load on the waveguide. This impedance can be designed to attenuate the signal flowing through the transmission line while minimizing radiation and can be activated by loading the slot with a diode. A prototype was fabricated to validate the proposed concept. The prototype was measured and it had an ON-state insertion loss of less than 1.3 dB, an OFF-state isolation of more than 10 dB, and a switchable bandwidth of 21% at 22 GHz.

An Electrostatic Discharge Protection Circuit Technique for the Mitigation of Single-Event Transients in SiGe BiCMOS Technology

The impact of electrostatic discharge (ESD) protection circuits on the single-event transients (SETs) of RF building blocks in a 130-nm SiGe BiCMOS (8HP) platform is investigated. For proof-of-concept that SET mitigation can be accomplished through the use of an ESD protection circuit, a single-pole single-throw (SPST) switch was implemented using triple-well nFETs. For substrate noise coupling suppression, a P+, P− substrate (Psub) and N-well guard ring structures were applied. According to two-photon absorption laser experiment results, the SPST switch with ESD protection exhibits the smallest transient peaks at the RF input/output and $\text{V}_{\mathrm {\mathbf {DD}}}$ ESD terminals. Based on these results, an SET mitigation strategy is proposed while maintaining the optimal circuit performance.

P-n-p-Based RF Switches for the Mitigation of Single-Event Transients in a Complementary SiGe BiCMOS Platform

The benefits of using p-n-p silicon–germanium (SiGe) heterojuction bipolar transistors (HBTs) in radio frequency (RF) circuits for the mitigation of single-event transients (SETs) have been investigated. As a representative circuit example, p-n-p SiGe-HBT RF single-pole single-throw (SPST) switches have been designed in a complementary SiGe BiCMOS platform. The fabricated p-n-p-based RF switches provide comparable RF performance to n-p-n-based switches. In terms of SET transient peaks and duration, the p-n-p SiGe HBT RF switches exhibit a significant reduction in SET sensitivity compared with their n-p-n counterparts. In the frequency domain, the p-n-p switches show fewer low-frequency spurs than that of the n-p-n switches. In addition, inverse-mode p-n-p SiGe HBT switches provide the best overall SET response among all RF SPST switches investigated.

Efficiency Improvement of Time Modulated Array With Reconfigurable Power Divider/Combiner

Time modulated array (TMA) suffers from relatively low efficiencies due to the power absorption in switches during off state. In this paper, we present the design of a novel TMA by using a reconfigurable power divider/combiner (RPDC) for improving the array’s efficiency, where the power absorbed during off state can evenly be transferred to other array elements during on state. An improved pulse sequence strategy is developed to control the radiation pattern of the TMA with RPDC. The impact of the RPDC on radiation features of the TMA is further discussed. To experimentally verify the feasibility of the proposed design, a six-element TMA with RPDC is constructed and characterized. Compared with a six-element conventional TMA with single-pole single-throw switches, the TMA with RPDC shows a significant enhancement of gain by 0.98, 1.27, and 1.65 dB when the sidelobe levels are −20, −25, and −30 dB, respectively.

High-Power Filtering Switch With Low Loss and High Isolation Based on Dielectric Resonator

In this paper, a novel method for designing high-power filtering switches using dielectric resonators (DRs) is presented for the first time. The filtering switches consist of DRs and printed circuit boards. The latter are embedded in the metal cavity to enable the integration of p-i-n diodes. The ON- and OFF-states are realized by controlling the p-i-n diodes which are put in the feeding lines or nonresonance nodes (NRNs). Electromagnetic field properties of the DR (at TE $_{11\delta }$ mode) and feeding line (or NRN) are studied and the coupling between them is investigated for guiding coupling control. In the ON-state, the filtering switches are equivalent to bandpass filters with no signal passing through the p-i-n diodes, which avoids additional loss introduced by p-i-n diodes and attains high power handling capability. In the OFF-state, the proposed filtering switches offer enhanced isolations by controlling the coupling of the filtering circuits, which differs from the conventional switches by turning off transistors or diodes. For demonstration, a DR-based filtering single-pole single-throw switch and a filtering single-pole double-throw switch are implemented. High selectivity, low ON-state loss and high OFF-state isolation are observed. The measured $\text{P}_{\mathrm {1dB}}$ is larger than 80 W, featuring high power handling capability.

Coupling-Inductor-Based Hybrid mm-Wave CMOS SPST Switch

This brief presents a hybrid CMOS millimeter-wave single-pole single-throw (SPST) switch. This newly invented hybrid structure demonstrates better tradeoffs between insertion loss and isolation compared to conventional distributed structures. The performance benefits are analyzed in detail and validated by both simulation and measurement results. Additionally, the chip area is conserved by using lump elements, the coupled inductor. Moreover, a specific bias scheme is used to further decrease insertion loss by about 0.5 dB. This SPST switch achieves higher than 35-dB isolation over an ultrawide frequency range, from 54 to 84 GHz, a minimum 1.7-dB insertion loss, and <−10-dB reflection coefficient with 0.012-mm2 chip area in 65-nm CMOS. The design achieves more than 10-dB enhancement of isolation in comparison with the state-of-the-arts while maintaining similar insertion loss.

High Power and Reliable SPST/SP3T RF MEMS Switches for Wireless Applications

This letter presents novel high power and reliable radio frequency (RF) microelectromechanical systems switches with single-pole single-throw (SPST) and single-pole triple-throw (SP3T) configurations. An in-plane movable structure with a single layer is made using a simple standard silicon-on-insulator process, which greatly reduces the micro-fabrication complexity and cost compared with the previously reported multi-contact switches with out-of-plane movable structures. The SPST switch achieves a uniform current distribution through each contact, thereby increasing the power handling capability of the switch. The SP3T switch is a derivative of the SPST switch with separate individual actuations. The experimental results demonstrate that the fabricated switches have superior RF performances: insertion losses are −0.9 and −1.3 dB at 6 GHz for SPST and SP3T switches, respectively, whereas isolations are better than −29 and −37 dB from dc to 6 GHz for SPST and SP3T switches, respectively. In hot-switching conditions, the SPST switch can handle RF power up to 2 W for 10 million cycles, whereas the SP3T switch is capable of handling an RF power of 1 W for 7 million cycles before failure occurs.

On-chip Josephson junction microwave switch

The authors report on the design and measurement of a reflective single-pole single-throw microwave switch with no internal power dissipation, based on a superconducting circuit containing a single Josephson junction. The data demonstrate the switch operation with 2 GHz instantaneous bandwidth centered at 10 GHz, low insertion loss, and better than 20 dB on/off ratio. The switch's measured performance agrees well with simulations for input powers up to −100 dBm. An extension of the demonstrated circuit to implement a single-pole double-throw switch is shown in simulation.