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This article has designed a bandpass filter using a coplanar stripline stub (CPS) resonator consisting of open and short‐ended strip lines connected to the PIN diode switches. The use of spurline stub resonators inside CPS results in bandpass and bandstop filters, depending on the PIN diode switch configurations. The work presents a novel circuit architecture aimed at reducing the parasitic resonance of the spurline resonators and acquiring the necessary series stub characteristics. The proposed filter resonates at 6.9–9, 1.7–4.7, and 8.4 GHz when the PIN diodes are forward and reverse‐biased, respectively. It also resonates at 1–2.1, 4.8–5.3, and 6.9–9 GHz when one diode is reverse‐biased, and the other is connected in forward bias. An insertion loss below −0.55 dB and a return loss less than 10 dB have been obtained during simulation and measurement. The designed filter can find different applications for the 1.8 GHz GSM band, 2.4/5.8 GHz (WLAN), 3.6 GHz (WiMAX), long‐term evolution (LTE), and WIFI. The filter can be used in various multi‐frequency systems owing to its compact size. The measured and simulated findings of the proposed CPS spurline stub resonator wideband bandpass filters are substantially consistent. [ABSTRACT FROM AUTHOR]

In this paper, an integrated device which realized the dual-mode integration of power amplifier (PA) and radio frequency (RF) switch based on GaN dual-gate (DG) structure is designed and fabricated. The integrated device provides two working modes and meets the performance requirements of PA and RF switch. In the transmit (Tx) mode, the integrated device is used as PA. At the frequency of 3.6 GHz, compared with the conventional GaN HEMT (high electron mobility transistor) as PA, due to the field modulation effect of the dual-gate structure, the current collapse is effectively suppressed, and the output power density $(P_{out})$ of the integrated device is increased from 6.90 W/mm to 7.85 W/mm, and the power added efficiency (PAE) is increased from 44.3% to 51.1%. In the receive (Rx) mode, the integrated device is used as RF switch. Compared with conventional RF switch, the isolation of integrated devices is significantly improved. At the frequency of 3.6GHz, the isolation is improved from 19.4 dB to 41.0 dB; At the frequency of 40 GHz, the isolation is improved from 3.0 dB to 29.7 dB. The integrated device provides a novel function integration scheme for RF frontends, with great potential for improving the integration and dimension of future communication systems.

A first modeling approximation of the general performance of radiofrequency (RF) switches based on hexagonal boron nitride (hBN), a two-dimensional (2D) dielectric material is presented. The I-V characteristics intrinsic and extrinsic impedance parameters, the return loss, insertion loss and isolation of RF 2D switches fabricated with hBN are described here by a equivalent circuit models. Straightforward analytical expressions are obtained. In contrast to conventional switches, the unique RF performance of the hBN switch, at ON-state, i.e., a direct improvement with frequency of the insertion loss, is accurately described by considering a capacitor in the intrinsic part of the model. The latter is suggested to be related to storaged charge during the resistive switching mechanism. The highest mean relative error obtained between modeling and measurements of the return loss is of 7.6% with the approach presented here which overcomes the 42.5% of difference obtained with a previous model with an incomplete intrinsic device description.

This paper presents two designs of millimeter-wave single-pole single-throw switches based on AlGaN/GaN heterostructure. The switches are based on two approaches to the travelling wave concept with Schottky barrier shunt elements integrated into a coplanar waveguide. The first design utilizes a two-stage artificial transmission line topology with distributed shunt elements in Schottky diode configuration. The second one employs a single electrically large shunt element configured as a high electron mobility transistor. Both arrangements allow the switches to achieve very high operational bandwidth, exceeding 100 GHz, without the requirement for very high lithography resolution. Examined switches were fabricated in a 2- $\mu \text{m}$ GaN-on-SiC process. Measurement results demonstrate upper operating frequencies exceeding 114.5 GHz starting from 14 GHz or even DC, depending on the design. The W band on-off ratio over 17 dB and 21 dB is achieved by the first and second construction, respectively. Measurements of transient parameters show that high switching speed can also be achieved (rise/fall time as low as ≤17 ns for the first construction).

This paper presents a fast switching and high-powered single-pole double-throw (SPDT) switch for RF switch circuits, such as TRx antenna switches and frequency band (or operation mode) selection switches in mobile handset applications. For fast switching time and performances of the RF switch, we proposed a novel method that can “selectively” control the impedance of a gate biasing circuit (“high” or “low” impedance). The proposed SPDT switch use the low impedance of the gate biasing circuit for fast switching time and use the high impedance of the gate biasing circuit to avoid the degradation of the insertion loss and harmonics. The proposed SPDT switch has no additional bias and no large payment for size consumption. According to measurement results, the turn-on switching time of the proposed SPDT switch was $0.35~\mu \text{s}$ (at 2 GHz). The insertion loss, isolation, and return loss at 2 GHz were 0.16 dB, 47.1 dB, and 24 dB respectively. 2nd and 3rd harmonic levels at 25 dBm input power at 2 GHz were −88.7 dBm and −78.9 dBm, respectively. Power handling capability was 39.5 dBm of input power at 2 GHz. The designed SPDT switch was implemented in a 0.13- $\mu \text{m}$ partially depleted silicon-on-insulator (PD-SOI) process.

This paper, we presents a RF protection technique of antenna switch by improving the power handling capability in worst case environment mode for mobile phone applications without critical payment of circuit performances such as insertion loss, isolation and ACBV (AC breakdown voltage). By applying a additional capacitive path located in front of the antenna in cell-phone, it performs the effective reduction of input power in high voltage standing wave ratio (VSWR) condition. Under the all-path off condition which causes a high VSWR, it achieved 37.7dBm power handling level as high as 5.7dB compared to that of conventional one at 2GHz. In addition, insertion loss and isolation performances were 0.31dB and 42.72dB at 2 GHz, respectively which were almost similar to that of the conventional circuit. The proposed antenna switch was fabricated in 130nm CMOS SOI technology [ABSTRACT FROM AUTHOR]

This article presents a four-element phased-array transceiver (TRX) front-end for millimeter-wave (mm-Wave) 5G new radio (NR). The effects of amplitude-to-phase (AM–PM) and amplitude-to-amplitude (AM–AM) distortions on error vector magnitude (EVM) are detailed. A three-stage highly linear wideband class-AB power amplifier (PA) is described, mitigating AM–PM and AM–AM distortions without degrading other performances. A matching network embedded transmitting/receiving (T/R) switch is proposed to support time division duplex (TDD). With the proposed technique, RF switch insertion losses are reduced in both transmitter (TX) and receiving (RX) modes. In each TRX element, phase and gain controls are achieved by a 6-bit vector-modulated phase shifter (VMPS) with a phase tuning range of 360° and a 6-bit attenuator with a gain tuning range of 31.5 dB, respectively. Fabricated in 65-nm bulk CMOS, the proposed packaged TRX demonstrates the measured peak gains of 25.5/14.2 dB with the gain ripples of less than 2.5/1.9 dB across 24–29.5 GHz in the TX/RX mode. The measured peak $P_{\text {1 dB}}$ is 17.6 dBm with a power added efficiency (PAE) of 20.4%. The measured minimum noise figure (NF) is 4.3 dB. The TRX achieves an output power of 7.9–8.9 dBm and an EVM of −25 dB with 8 $\times $ 100-MHz 5G NR frequency range 2 (FR2) orthogonal frequency division multiplexing (OFDM) 64-quadrature amplitude modulation (QAM) signals across 24–29.5 GHz, covering 3rd generation partnership project (3GPP) 5G NR FR2 operating bands (i.e., n257, n258, and n261) around 26 GHz. [ABSTRACT FROM AUTHOR]

In modern communication systems, the use of multiband approach, where the frequency bands can be selectable, is highly desired to achieve the highest wireless data rate and can also reduce transceiver complexity, size, and cost. This article presents, for the first time, a fully integrated band-switchable CMOS power amplifier (PA) utilizing a pioneering approach toward switching impedance matching networks. In the proposed approach, which is called bit optimized reconfigurable network (BORN), an $n$ -bit BORN may create ($2^{n} -1$) number of switchable frequency bands utilizing only one active block and only $n$ -number of impedance matching network arms controlled by applying digital bits to switches. As a proof of concept, a 2-bit BORN PA is designed and fabricated in a 0.18- $\mu \text{m}$ CMOS process with a die size of 3.1 mm $\times1.6$ mm, which covers three bands of interest by utilizing only two input/output matching networks. The proposed 2-bit BORN PA delivers the saturated output power ($P_{\mathrm {sat}}$) of 21.3/22.3/23.0 dBm, the output 1-dB compression point ($P_{\mathrm {1\,dB}}$) of 19.5/20.0/21.0 dBm, and the 3-dB bandwidth of 400/425/550 MHz at the three targeted frequency bands, respectively. The measured results show promising improvement with respect to the state of the art. [ABSTRACT FROM AUTHOR]

With the evolution of radio frequency (RF)/microwave technology, there is a demand for circuits that are able to meet highly challenging RF front end specifications. Silicon-on-insulator (SOI) technology is one of the leading platforms for upcoming wireless generation. The degradation of performance due to substrate coupling is a key problem to address for telecommunication circuits, especially for the high throw count switches in RF front ends. In this context, a fast, flexible and local laser ablation technique of the silicon handler allows for the membrane suspension of large millimeter-scale circuits. This approach enables the evaluation of the ultimate performance in the absence of the substrate, i.e., without dissipative losses and substrate-induced non-linear effects, on capacitive comb coupling structures and RF switches. Compared to high-resistivity SOI substrates, the high frequency characterization of RF membrane switches reveals a superior linearity performance with a reduction in second and third harmonics by 17.7 dB and 7.8 dB, respectively. S-parameter analysis also reveals that membrane suspension entails insertion losses that are improved by 0.38 dB and signal reflection lowered by 4 dB due to a reduced off-state capacitance. With reference to a trap-rich substrate, the membrane suspension also achieves an additional 7.8 dB reduction in the second harmonic, indicating that there is still scope for improvement in this figure of merit. The obtained results demonstrate a new way to evaluate optimized circuit performance using post-fabrication substrate engineering. [ABSTRACT FROM AUTHOR]

This paper presents a radio frequency (RF) triple pole triple throw 3P3T cross antenna switch for cellular mobile devices. The negative biasing scheme was applied to improve the power-handling capability and linearity of the switch by increasing the maximum tolerable voltage drop across the drain and source and reverse biasing the parasitic junction diodes. To avoid signal reflection through the antenna in off-state, all the antenna ports were equipped with 50-ohm termination to provide the pull-down path. Considering the simultaneous operation of antenna ports in different switch cases, the presented T-type pull-down path demonstrated improvement of isolation by over 15 dB. Using stacked switches, the 3P3T handled the input power level of over 35 dBm. The chip was manufactured in 65 nm complementary metal oxide semiconductor (CMOS) silicon on insulator (SOI) technology with a die size of 790 × 730 µm. The proposed structure achieved insertion loss, isolation, and voltage standing wave ratio (VSWR) of less than −0.9 dB, −40 dB, and 1.6, respectively, when the input signal was 3.8 GHz. The measured results prove the implemented switch shows the second and third harmonic distortion performances of less than −60 dBm when the input power level and frequency are 25 dBm and 3.8 GHz, respectively. [ABSTRACT FROM AUTHOR]

This paper proposes a stacked field-effect transistor (FET) single-pole, double-throw (SPDT) RF switch which is capable of multi-standard. Negative voltage generator (NVG), logic controller, level shifter, and RF Switch branches are integrated. A PMOS self-biased strategy is proposed to improve linearity and simplify the design of the logic controller and level shifter. In order to reduce the influence of NVG, a new charge pump (CP) is proposed, and a low pass filter (LPF) is added to stabilize bias voltages. A new layout of the switch FET is proposed to minimize the product of on-state resistance and off-state capacitance (time constant). The RF switch proposed in this paper was implemented in the 0.18 μm silicon on insulator (SOI) process. The measured results show the P1 dB of 40 dBm, and the isolation (ISO) and insert loss (IL) at 1 GHz/5 GHz of 37 dB/22 dB, and 0.36 dB/0.55 dB. The operating frequency range is DC-6 GHz. Supply current is 37uA with the supply voltage of 2.6V. [ABSTRACT FROM AUTHOR]

Power-handling capability of bulk CMOS-based single-pole double-throw (SPDT) switch operating in millimeter-wave (mm-wave) and subterahertz region is significantly limited by the reduced threshold voltage of deeply scaled transistors. A unique design technique based on impedance transformation network (ITN) is presented in this work, which improves 1-dB compression point, namely P1dB, without deteriorating other performance. To prove the presented solution is valid, a 70–100-GHz switch is designed and implemented in a 55-nm bulk CMOS technology. At 90 GHz, it achieves a measured P1dB of 15 dBm, an insertion loss (IL) of 3.5 dB, and an isolation (ISO) of 18 dB. The total area of the chip is only 0.14 mm2. [ABSTRACT FROM AUTHOR]

A new structure for low‐loss and high‐isolation radio‐frequency microelectromechanical systems (RF MEMS) switches is presented. The high contact force of the switch leads to very small ranges for contact resistance which is the main constrain of DC‐contact RF MEMS switches. The contact resistance of the switch is 27 mΩ leading to negligible thermal noise which is one of the most important parameters for devices operating at RF front‐ends immediately after the antenna where there is not any active stage. The switch is composed of two actuators: an electrothermal actuator for actuation of the switch from OFF to ON state and an electrostatic actuator to hold the switch at ON state. The insertion loss, return loss, and isolation of the switch for frequencies below 70 GHz are −0.35, −20, and −10 dB, respectively. The contact force and contact resistance of the switch are 0.93 mN and 0.027 Ω, respectively. Electrothermal and electrostatic actuators require 0.91 and 50 actuation voltages, respectively. During the ON‐state, the power consumption of the switch is near zero. The low contact resistance and high‐isolation characteristics of the switch make it very suitable for mobile front‐ends. [ABSTRACT FROM AUTHOR]

In this communication, a low-cost, single-pole double-throw (SPDT) filtering radio frequency (RF) switch based on coupled resonators is proposed and utilized in a novel pattern reconfigurable antenna design. The proposed filtering switch employs two second-order quarter-wavelength microstrip resonant structures which can be controlled by p-i-n diodes, respectively. Compared with traditional switches based on p-i-n diode, this filtering switch can not only improve the RF response but also suppress the high-order harmonic, when it is used with an antenna. Then, a low-profile dual-port broadside/conical dual-mode antenna is proposed by embedding a slotted substrate integrated waveguide (SIW) cavity in the middle of a patch antenna. The slotted cavity is to realize the radiation in the broadside whereas the patch is fed by two probes in-phase to realize the conical radiation. Finally, the filtering switch and the dual-mode antenna are combined to realize the pattern reconfigurable antenna. By controlling the states of the p-i-n diodes, broadside and conical radiation patterns can be easily switched. The concept of switch-based pattern reconfigurable antenna is prototyped and experimentally verified. Measured results agree with the simulations, demonstrating a promising solution for pattern reconfigurable antenna designs. [ABSTRACT FROM AUTHOR]

A frequency-reconfigurable SP4T switch is presented, in which ${R}_{\text {ON}} \times {C}_{\text {OFF}}$ characteristics of switch transistors are enhanced with plaid metal transistors and forward body biasing. Plaid metal transistors (PMT) with forward body bias (FBB) are used for all of the transistors to enhance the FoM. The plaid patterned metal accesses of a transistor for the source and drain decrease the extrinsic resistance and capacitance. FBB increases the overdrive voltage of a transistor and decreases the on-resistance. The SP4T switch includes main switch matrices that route an input signal to four-outputs, a switched inductor (SI) network, and a mode-selection switch. The SI network connected through the mode-selection switch resonates out the off-capacitances of the main switch matrices at RF in the RF mode. The SP4T switch operates without the SI network in DC mode. The SP4T switch is implemented in a 28-nm FDSOI CMOS process. The core area occupies 0.2 mm2. The switch shows less than 2 dB insertion loss from DC to 4.4 GHz in the DC mode and from 4.4 to 5.3 GHz in the RF mode, where isolations are more than 16.8 dB and 18 dB, respectively. [ABSTRACT FROM AUTHOR]

This article presents millimeter-wave (mmWave) chalcogenide nonvolatile phase change material (PCM) germanium-telluride (GeTe)-based scalable switch matrices in a crossbar configuration. Two crossbar switch matrices in the form of $2 \times 2$ and $4 \times 4$ configurations are designed utilizing PCM four-port crossbar unit cells designed to have two states. The presented $2 \times 2$ switch matrix utilizes a maximum of only two series PCM switches in any possible signal route, minimizing the insertion loss. A switch unit cell is optimized in terms of design and signal routing to improve the RF performance. The nonvolatile PCM switches consume no static dc power. The proposed switch matrices are fabricated in-house using an eight-layer custom microfabrication process. A design approach for scaling to higher order matrices is discussed, with an experimental demonstration of a $4 \times 4$ switch matrix. Both $2 \times 2$ and $4 \times 4$ switch matrices are ultra-compact in size with the device area under 0.1 mm2 for $2 \times 2$ and less than 0.38 mm2 for $4 \times 4$ switch matrix. Over dc to 40 GHz, the fully integrated $2 \times 2$ switch matrix exhibits a measured insertion loss less than 1.35 dB, a return loss better than 20 dB, and isolation higher than 24 dB. The $4 \times 4$ switch matrix demonstrates a measured insertion loss of lower than 4.2 dB, a return loss better than 18 dB, and isolation better than 26 dB over the entire 40 GHz bandwidth. In addition, utilizing the scalability approach, two crossbar switch matrices of order $4\times12$ and $16\times16$ are also developed for dc/low-frequency switching applications. [ABSTRACT FROM AUTHOR]

Three RF switches and a phase shifter are proposed using the conductive bridging random access memory (CBRAM) technique. The fabrication process is developed with the Nafion membrane on a high-resistivity silicon substrate. The equivalent circuit model is established for each memristive RF switch. The proposed switches and the phase shifter have been validated by the good agreement achieved among the simulated, measured, and modeled results. The experimental results show that the series planar switch has the ON-state insertion loss (IL) below 1.69 dB and the OFF-state isolation over 25 dB up to 10 GHz, with the actuation voltages of 6.1~7.8/−1.5~−2 V. The parallel metal–insulator–metal (MIM) switch has the small ON-state IL below 0.45 dB and the OFF-state isolation over 18.4 dB when biased with 0.8~3.7/−0.5~−0.9 V. The series MIM switch has the ON-state IL below 0.61 dB and the OFF-state isolation over 21.9 dB with 0.7~2.3/−0.5~−0.9 V. The series MIM switch shows a good comprehensive performance of low actuation voltage, good uniformity, low IL, moderate isolation, and independent control. The phase shifter is realized with four series MIM switches, which provides a phase shift of 45° ± 5° from 3.8 to 4.3 GHz with the in-band IL of 2.25 dB. Compared with the conventional RF switchable devices, the proposed devices have the advantages of nonvolatility and low power consumption. Without depending on the electron beam lithography process and high-temperature phase change, the proposed technique is promising for reconfigurable RF circuits with mass production and feasibility to various substrates. [ABSTRACT FROM AUTHOR]

This paper proposes an electronically reconfigurable multimode orbital angular momentum (OAM) patch array antenna using single pole double throw radio frequency switch that can complete dynamic switching of three modes (-1,0,1) at 2.4 GHz. As a new type of multiplexing technology, the application value of OAM technology in radar imaging and wireless communication has been continuously verified. Considering that many theoretical algorithms are proposed, a multimode vortex antenna that meets the experimental requirements should be developed. The proposed antenna consists of RF switch, programmable microcontroller, phase-shifted feed network, and $2\times2$ rectangular array. Different feeder networks were selected by controlling the RF switch to generate vortex beams with different modes. The proposed antenna was numerically simulated and physically produced. The feasibility of the design was verified through experiments. The simulation and design results are basically the same. The proposed scheme has simple structure, easy to design and deploy, and has important significance in the design of many mode vortex antenna applications in communication and radar imaging.

Recently, a concept of linear wireless sensor networks (LWSNs) has attracted much attention. For such networks, one of the key challenges in sensor node design is to couple transceiver modules with bidirectional antennas placed back‐to‐back for opposite radiation. As is known, simply, this can be achieved by using well‐known coupling options like radio frequency (RF) switch or splitter. However, it is important to decide between two seemingly equally good options according to the system requirements such as RF performance, power consumption, and cost. Therefore, this study aims to comparatively assess these options from the system level point of view to find out what advantages or disadvantages either provides as per the other from widespread use of them in a LWSN‐based cathodic protection monitoring of oil and natural gas pipelines in extreme environments. Preliminary field tests are also conducted to validate the efficiency of coupling options for LWSN links. Results show that RF splitter offers low power consumption and cost whereas RF switch has advantages of low loss. Thus, it is believed that this study may provide useful insights to design bidirectional sensor links for LWSNs. [ABSTRACT FROM AUTHOR]

This paper reports two configurations of non-volatile multiport transfer switches based on the phase change material (PCM) germanium telluride. The monolithic transfer switches are developed in-house using a custom microfabrication process designed to operate over a wideband dc–30GHz. A C-type switch configuration is presented with two operational states in a highly miniaturized package with the device core area under 0.09mm2. A unique, highly versatile multiport R-type switch configuration is proposed with three operational states that offers improved system flexibility, reducing the number of switches for routing. The R-type switch configuration has a device core periphery under 0.2mm2. The presented devices are compared with the current state-of-the-art switch technologies. The transfer switches exhibit a measured insertion loss of less than 1.5dB, return loss better than 18dB, and +35.5dBm measured power handling capability with switching speed less than 2 $\mu \text{s}$. [ABSTRACT FROM AUTHOR]

This paper investigates the characteristics of a micro-switch that uses two side electrodes to open a normally closed switch. The side electrodes surround the fixed electrode in the well-known gap-closing electrode configuration. The side electrodes can open a closed switch and be tuned to respond appropriately to outside forces. The combined electrode system dramatically improves the control of a standard gap-closing electrode configuration. In conventional switches, a DC voltage above a certain value closes the switch. To reopen the switch, the voltage difference is reduced to peel off the moving electrode. Currently, the contact area is carefully designed to avoid stiction, but the degradation over time and stiction forces can cause a permanent failure. In this work, opening occurs by feeding the side electrodes a voltage beyond a certain value that results in a levitation force. Even if the degradation in the surfaces happens, the switch can open by increasing the side voltages. The characteristics of the combined actuation system are thoroughly analyzed and include the static pull-in, static displacement, release voltage, dynamic pull-in, frequency response, and basins of attraction. The results are validated by the experimental tests. The levitation-based micro-switch improves the system tunability as the sensitivity and switching thresholds can be adjusted. [ABSTRACT FROM AUTHOR]

Embedded systems are generally powered by batteries, characterized by a limited duration of electrical energy storage. For that, low power consuming RF components are often used. This work focuses on the design of a new RF switch based on one varicap diode within a series/parallel circuit topology. The latter is low-power-consuming in both ON and OFF mode and inhibits eventual nonlinearities caused by series diodes such as common PIN diodes. Before performing simulations, the diode has been characterized experimentally in the whole UHF band of interest and the extracted S-parameters have been used in the simulations of the resonating structure. The optimized switch has been measured and has showed a good agreement with simulated results in terms of high isolation (50 dB) and low insertion loss (0.1 dB). These results showed better performances compared to other structures based on RF MEMS, PIN diode or FET transistor devices, available in the literature.

Based on commercial 0.2 μm SOI RF process platform, the influence of stack, width, bias resistance and bias voltage on scatter parameter characteristics of test structure for SOI RF switch application is investigated, including series branch, shunt branch, single-pole-single-throw, and single-pole-double-throw. The impacts of different design on RF switch insertion loss and isolation are discussed in detail. The result can be reference as device optimization and circuit design.

This paper presents a radio frequency (RF) triple pole triple throw 3P3T cross antenna switch for cellular mobile devices. The negative biasing scheme was applied to improve the power-handling capability and linearity of the switch by increasing the maximum tolerable voltage drop across the drain and source and reverse biasing the parasitic junction diodes. To avoid signal reflection through the antenna in off-state, all the antenna ports were equipped with 50-ohm termination to provide the pull-down path. Considering the simultaneous operation of antenna ports in different switch cases, the presented T-type pull-down path demonstrated improvement of isolation by over 15 dB. Using stacked switches, the 3P3T handled the input power level of over 35 dBm. The chip was manufactured in 65 nm complementary metal oxide semiconductor (CMOS) silicon on insulator (SOI) technology with a die size of 790 × 730 µm. The proposed structure achieved insertion loss, isolation, and voltage standing wave ratio (VSWR) of less than −0.9 dB, −40 dB, and 1.6, respectively, when the input signal was 3.8 GHz. The measured results prove the implemented switch shows the second and third harmonic distortion performances of less than −60 dBm when the input power level and frequency are 25 dBm and 3.8 GHz, respectively.

This paper presents a theoretical analysis for achieving uniform voltage distribution among stacked field effect transistors (FETs) of RF tuner switch. The RF peak voltage (Vpeak) is limited by the unequal divided voltage drop among stacked FETs. A simplified equivalent capacitor circuit is established and an analytical expression is then derived for the first time to decide the value of ideal equivalent capacitance of each FET in the stack for achieving equal voltage division. Varying size of each stacked FET to set that the drain‐to‐source capacitance (Cds) equals to the capacitance from the proposed analytical expression can obtain a uniform voltage distribution, and thus a much higher Vpeak. To validate the proposed analytical expression, a 4‐shunt single‐pole single‐throw (4xSPST) switch is fabricated in HHGrace's 0.13 μm RF silicon‐on‐insulator process. Simulation and measurement results show that the switch features a uniform voltage distribution and a significant improvement in Vpeak. [ABSTRACT FROM AUTHOR]

In this paper, a reconfigurable ring resonator‐based filter integrated switch (FIS) was presented. The FIS was made up of two absorptive ring resonators, reconfiguring between band‐stop and band‐pass responses, and integrated with single pole double throw (SPDT) switch. A simple mathematical analysis of isolation and insertion loss of filter‐integrated SPDT switch was discussed. PIN diodes were used as the switching elements for the SPDT switch and to reconfigure between the band‐stop and band‐pass responses. The proposed absorptive FIS design could be used for wireless data communication systems such as Zigbee and Bluetooth at an operation frequency of 2.45 GHz. As a result, the proposed FIS exhibited 2 dB of insertion loss and better than 38 dB of isolation. Therefore, the key advantages of the proposed FIS design are low insertion loss, high isolation and good return loss at both ON‐ and OFF‐state ports. [ABSTRACT FROM AUTHOR]

This paper evaluates the small-and large-signal characteristics of a single pole double thru (SPDT) RF antenna switch including its insertion loss, isolation, and nonlinear behavior. It is fabricated on three different types of high resistivity (HR) silicon-on-insulator (SOI) substrates: one standard (HRSOI) and two trap-rich (RFeSI80 and RFeSI90). Using a special test structure, the contribution of substrate and active devices is separated for both in small-and large-signal. It is shown that by using trap-rich substrate technology, a reduction of over 16 dB of 2nd harmonic is achieved compared with HR SOI substrate. In off-state, it is shown that 35 dB increase of harmonic level is due to the nonlinearity of active devices. The effect of body bias on small-and large-signal FoMs of the SPDT is investigated and discussed. It is illustrated that trap-rich HR-SOI substrates having much thinner BOX, still outperform classical HR-SOI wafer.

This paper presents the design, fabrication, and electrical characterization of a reconfigurable RF capacitive shunt switch that exploits the electro-thermally triggered vanadium dioxide (VO2) insulator to metal phase transition. The RF switch is further exploited to build wide-band RF true-time delay tunable phase shifters. By triggering the VO2 switch insulator to metal transition (IMT), the total capacitance can be reconfigured from the series of two metal-insulator-metal (MIM) capacitors to a single MIM capacitor. The effect of bias voltage on losses and phase shift is investigated, explained, and compared to the state of the art in the field. We report thermal actuation of the devices by heating the devices above VO2 IMT temperature. By cascading multiple stages a maximum of 40° per dB loss close to 7 GHz were obtained.

Four-terminal, inline, indirectly heated phase-change switches (IPCS) have emerged as great contenders for reconfigurable radio frequency (RF) integrated circuits, providing state-of-the-art cutoff frequency thanks to their built-in dc-RF decoupling. However, the switching of IPCS devices is determined by their temperature which is challenging to predict. In this article, we present a physics-based compact model of the IPCS, validated by finite-element method simulations and measurements of IPCS devices. The model accurately predicts the thermal and electrical dynamics of the device by considering the changes in heater resistance, contact resistance, and parasitic capacitance. The complete model is implemented in Verilog-A, and a downloadable version is freely available at the nanoHUB.org. We show how the compact model can be used for rapid device evaluation and optimization between RF performance and energy efficiency. Nanosecond electrical thermometry of the heater for varying pulses during IPCS device operation and RF measurements is used to experimentally validate the model. [ABSTRACT FROM AUTHOR]

This paper reports the development of piezoelectrically actuated radio frequency (RF) micro-electromechanical systems (MEMS) switches on Si-on-sapphire substrates using a novel greyscale lithography fabrication technique. Lead zirconium titanate (PZT) thin-film actuators are used to close a series ohmic contact single-pole single-throw (SPST) switch implemented in co-planar waveguide (CPW). The switch design on a Si substrate has maximum insertion loss of 2.6 dB from DC – 67 GHz. While over the same frequency span, the switch on a sapphire substrate exhibits insertion loss better than 1.4 dB and isolation better than 15 dB. [2020-0071] [ABSTRACT FROM AUTHOR]

Modern wireless devices operate on multiple frequency bands and, thus, can benefit from frequency-reconfigurable radio frequency (RF) components, especially filters that are typically larger in size and are required for every frequency band. In addition, many applications, such as wearable electronics, desire stable performance from the devices when they are bent or flexed. However, most of the reconfigurable filters are built on rigid substrates and utilize expensive discrete RF switches, which needs to be soldered to the filters. In this work, we present a fully printed filter that achieves reconfigurability through printed vanadium dioxide (VO2)-based switches that are extremely low cost and do not require any soldering for their attachment. The filter design is based on a dual-mode resonator, which enables a second-order filter despite a single resonator, thus helping in making the filter compact. It also helps in maintaining a decent insertion loss (2.6 dB), despite relatively low conductivity of the metallic ink. The switches, when activated thermally through a printed heater at the backside, reconfigure the frequency from 4 to 3.75 GHz. The filter has been realized on a flexible Kapton substrate, making the filter conformable to any surface. Measurements under various bending conditions reveal stable performance, making this filter design suitable for a number of wearable and the Internet-of-Things applications. [ABSTRACT FROM AUTHOR]

Generally, two synchronized transmitters are required to implement transmit diversity, such as Alamouti codes. However, because two transmitters are used, many disadvantages arise, such as increased price, power consumption, complexity, and the necessity of synchronization and calibration. In this paper, we proposed a new method to realize transmit diversity only using one transmitter. The proposed method combines baseband signal processing and an RF circuit, which connects a 180° hybrid and one switch between one transmitter and two transmit antennas, and controls the switch at the mid-point of the transmission bit. Because the proposed system has only one transmitter, the power consumption and hardware cost can be reduced by half, and the diversity gain can be realized in a fading environment. We verified the feasibility of the proposed method by computer simulations and confirmed that diversity operation can be realized using hardware. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

A method for complex RF impedance sensing is proposed. The method is based on using a scalar impedance meter and an impedance tuning network for sensing the complex load impedance. The scalar measurements are conducted three times for different settings of the digitally controlled tuning network after which the load impedance is evaluated based on the scalar outputs from the reflectometer. The measurements of the prototype device are demonstrated. The target application for the presented system and method is the antenna-tuning front end of the multiantenna cellular handheld devices. [ABSTRACT FROM AUTHOR]

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This article reports signal processing and circuit techniques for direct RF signal modulation. A pulse-encoded transition (PET) technique is introduced to reduce undesired harmonic distortion (HD) and adjacent channel leakage ratio (ACLR) generated by the direct RF modulation. To enable PET RF switching, two variations of a high-power, stacked-FET switch modulator, an 8- and 12-device stack, are designed in 45-nm silicon on insulator (SOI) CMOS. The switch design uses a tapering design to significantly improve power handling with minimal impact to switching speed. The modulators have $P_{1\,{\mathrm{ dB}}} $ values between 34 and 39 dBm while demonstrating a modulation bandwidth of nearly 500 MHz with a 1-GHz carrier. The input referred third order intercept point (IIP3) is between 46 and 61 dBm. Additionally, ACLR measurements of up to −50 dBc are demonstrated using the proposed PET technique at 30-dBm output power. To the best of our knowledge, this is record power handling and ACLR for a CMOS switch. [ABSTRACT FROM AUTHOR]

Microwave imaging is an emerging technology in the medical application which have similar functions as X-ray, Magnetic Resonance Imaging (MRI), and Computed Tomography scan (CT scan). In designing a microwave imaging system for medical application, it can use a monostatic radar approach by transmitting a Gaussian pulse (with an ultra-wideband (UWB) frequency). In this system, eight antennas are required with the support of RF switches. Thus, it is important to get the best performance of UWB RF switch in this application. Therefore, this paper presents the performance analysis of four different RF switch topologies (Design 1, 2, 3 and 4) using discrete PIN diode in SC-79 package. The design was based on single pole double throw (SPDT) switch. As result, Design 2 is the best topology after considering the tradeoff between isolation and return loss performances. Based on the three cascaded SPDT switches of Design 2, the insertion loss was less than -2 dB and return loss was more than -10 dB. Meanwhile, the isolation bandwidth (at the minimum isolation of -20 dB) was from 0.5 to 3.7 GHz (with 3.2 GHz bandwidth), hence, it could be used in the UWB frequency for medical application of microwave imaging. [ABSTRACT FROM AUTHOR]

A novel printed circular monopole antenna with bandwidth more than ultra- wide band along with reconfigurable single, dual and triple notch band is presented. The antenna provides bandwidth of 3.04 – 17.2 GHz by generating additional resonances towards higher end with modified ground structure. Moreover, the reconfigurable notches at WiMAX, WLAN and downlink of X band satellite communication are designed using slot technique to reduce interference at these wireless services if present. Thus, designed antenna provides a good solution for spectrum sensing and dynamic spectrum access as required in cognitive radios. The reconfiguration of notch bands is experimented using 0 ohm surface mounted resistors to show RF switching.

A compact filtering switch with wide-stopband responses is presented in this paper. The resonator is designed using microstrip transmission lines and lumped capacitors. It is utilized to shift up the second harmonic frequency for wide-stopband performance and miniaturize the circuit size. In the ON-state, the circuit is the same as the bandpass filter without signals passing through the p-i-n diode, which avoids additional loss introduced by p-i-n diode. Two transmission zeros are generated near the passband to enhance the skirt selectivity. In the off-state, the signals from port 1 to port 2 passing through different transmission path are cancelled out, resulting in high isolation. For demonstration, a filtering switch operating at 780 MHz is implemented with the compact size of 0.072λg×0.066λg. More than 20-dB suppression levels are measured from 0.89 to 5.3 GHz (6.8 f0), featuring wide-stopband responses.

In general, a direction finding system based on array antennas is implemented using a digital beamforming method with the same number of receivers as antennas, or using an RF beamforming method where a single receiver has a plurality of phase shifters. However, both approaches require complicated hardware configurations, which is a major disadvantage. In this paper, we propose a new method to generate 4-beam patterns using only two antennas and a single receiver with a sum and difference pattern of 180° hybrid, and the orthogonality of an I/Q demodulator. To verify the proposed method, we applied it to a Bluetooth direction finding system. The simulation results demonstrated that it is possible to implement an effective direction finding system using the proposed method. [ABSTRACT FROM AUTHOR]

In this paper, a new wideband RF MEMS switch using lateral and vertical actuations has been proposed which can be used for wide frequency band. The switch consists of one side clamped bridge and two electrostatic actuators array which move the bridge laterally. There is also one vertical electrostatic actuator which moves the bridge up and down. This actuation voltage is equal to 15 V. A flexible hinge is used in the proposed structure, which has a little spring constant in the lateral direction. Thus, by applying a small voltage, the switch bridge can be moved laterally to left or right and it changes the capacitive area between the bridge and RF signal line both in up and down positions. Depending on left or right electrostatic actuation forces, the bridge moves to left or right and the switch capacitive area is increased or decreased. The lateral actuation voltage of the proposed switch is equal to 2 V. Briefly, the switch can operate in wider bandwidth than conventional structure which consists of only vertical actuator. The simulations are done by HFSS and COMSOL softwares. The bandwidth of this switch is from 4.5 to 10 GHz. [ABSTRACT FROM AUTHOR]

This paper describes Ka-band inductor-shared RF switches and their applications to a 35.2-ps 6-bit true-time-delay (TTD) switched-line (SL) phase shifter (PS). The inductor-shared RF switches share an inductor to match the input and output (I/O) ports of different states, which are realized with a switched inductor for SP ${n}\text{T}$ case and with a shared matching network for DP ${n}\text{T}$ case. The switches are applied to controlling most significant 3 bits of the proposed TTD SL PS. The delay lines and reference lines of the PS are implemented with microstrip lines and inverted microstrip lines in the same space, respectively. The dual-side microstrip lines allow it to have not only a small size but also compensation of the loss difference between the signal lines with different lengths. The least significant 3 bits are implemented with the modified structure of the SL PS, which reduces the size further by replacing a reference line by a series switch. The test chip is fabricated in a 65-nm CMOS process. It operates in the range of 20–30 GHz occupying a 0.18 mm2 core size. Its measured insertion loss and IP1dB are 11 dB and 6.5 dBm at 28 GHz, respectively. The measured gain error and rms delay error are less than 2 dB and 0.7 ps at operation frequencies. [ABSTRACT FROM AUTHOR]

Embedded systems are generally powered by batteries, characterized by a limited duration of electrical energy storage. For that, low power consuming RF components are often used. This work focuses on the design of a new RF switch based on one varicap diode within a series/parallel circuit topology. The latter is low-power-consuming in both ON and OFF mode and inhibits eventual nonlinearities caused by series diodes such as common PIN diodes. Before performing simulations, the diode has been characterized experimentally in the whole UHF band of interest and the extracted S-parameters have been used in the simulations of the resonating structure. The optimized switch has been measured and has showed a good agreement with simulated results in terms of high isolation (50 dB) and low insertion loss (0.1 dB). These results showed better performances compared to other structures based on RF MEMS, PIN diode or FET transistor devices, available in the literature. [ABSTRACT FROM AUTHOR]

Atomic clocks provide frequency reference signals for communication, aerospace, satellite navigation and other systems. The redundant configuration of atomic clocks is necessary for ensuring the continuity and stability of the system. A radio frequency (RF) switch is usually used as a switching device in the switching system of the host atomic clock and the backup atomic clock. When the atomic clock fails, the switching between the host and the backup clock can be carried out quickly. Aiming at the fast switching requirements of atomic clock RF signals, this paper proposes a new series-shunt Positive Intrinsic Negative (PIN) switch design. In this paper, the evaluation of the RF switches is conducted by using the metrics of switching speed, insertion loss, isolation, return loss at on state and return loss at o state. Experimental result shows that the new PIN switch has better and more comprehensive performance metrics than the electromechanical switch, FET switch and conventional PIN switch. In particular, the switching speed is 53 ns faster than the conventional series-shunt PIN switch. [ABSTRACT FROM AUTHOR]