Very small control modules with line unified FET configuration forarray processing

Very small, broadband circuit function modules which operate as signal pass switches, phase inverters, and balanced modulators are proposed. They are realized by mutual on/off switching of the FETs in the line-unified FET configuration, with which a main circuit function can be realized in almost the same size as a conventional FET. It is demonstrated that a balanced modulator with a chip size of only 0.6 mm×0.5 mm can control signal gain from 0.7 to -0.7 continuously, while input and output impedances are independent of control bias and isolation is more than 35 dB and up to 18 GHz. These circuit function modules are valuable in constructing miniaturized phase shifters and highly integrated circuits for array processing     

Design Considerations for Traveling-Wave Single-Pole Multithrow MMIC Switch Using Fully Distributed FET

The circuit design considerations for the traveling-wave switch (TWSW) single-pole double-throw (SPDT) monolithic microwave integrated circuit (MMIC) utilizing a fully distributed FET (FD-FET) are presented here for the first time. The normalized length of the impedance transformer for a single-pole multithrow TWSW using the FD-FET is found to be less than a quarter-wavelength at the operating frequency. Unlike the TWSW using lumped FETs, the TWSW with the FD-FET offers the advantage of no design limits regarding such frequency characteristics as bandwidth and group delay. The newly developed SPDT TWSW MMIC using the 400-mum-gate finger FD-FET delivers broadband characteristics over more than an octave frequency range with highly reliable MMIC technology. The newly developed SPDT MMIC switch provides low insertion loss of less than 2.1 dB and high isolation of over 25.5 dB from 38 to 80 GHz, coupled with the benefit of very small size     

A High-Power CMOS Switch Using A Novel Adaptive Voltage Swing Distribution Method in Multistack FETs

A high-power CMOS switch using a novel adaptive voltage swing distribution method in a multistack field-effect transistor (FET) scheme is proposed. The proposed adaptive voltage swing distribution method in multistack FETs is very effective in preventing unwanted channel formation with low control voltage supply in OFF-state FETs. This, in turn, increases power-handling capability when a large-signal voltage swing is applied. In the proposed CMOS switch, the behavior of the voltage swing in OFF-state multistack FETs shows a difference with respect to the level of input voltage swing. The characteristics of voltage swing distribution and leakage channel formation in the CMOS switch is fully analyzed with incorporation of the novel adaptive voltage swing distribution method into a three-stacked nMOS Rx switch in a standard 0.18-mum triple-well CMOS process. In addition, linearity of the proposed technique is verified through the measurement data of the single-pole double-throw switches that employ the proposed technique in the Rx switch. Two different types of configurations are implemented and characterized at the Rx switches, which consist of four-stacked nMOS devices, to demonstrate the method of minimizing voltage stress issues on one of the multistacked FETs. Layout consideration was also taken to prevent interference between leakage signals at the substrate. The measured performance of the proposed design shows an input 0.3-dB compression point of 33.5 dBm at 1.9 GHz. To the best of our knowledge, this is the highest power-handling capability of a CMOS switch in a standard CMOS process ever reported. The insertion losses of the Tx and Rx switches are 1.6 and 1.9 dB, respectively, at 1.9 GHz. The isolation of the Tx and Rx switches is around 20 and 30 dB, respectively, at 1.9 GHz.     

High power DPDT antenna switch MMIC for digital cellular systems

In this paper, we propose two new types of dual-pole double-throw (DPDT) switch GaAs JFET monolithic microwave integrated circuits (MMICs) for digital cellular handsets. These ICs have the excellent characteristics of low insertion loss and high power handling capability, even with a low control voltage by stacking three JFETs with shallow V_p and using a novel bias circuit using p-n junction diodes. One DPDT switch IC has two shunt FET blocks and can achieve high isolation without external parts. An insertion loss less than 0.6 dB and isolation over 25 dB up to 2 GHz were achieved. P_1dB was about 35 dBm even with a control voltage of 0/3 V. Another DPDT switch IC utilizes parallel resonance of external inductors and parasitic capacitance between the drain and the source of the OFF-state FETs. By attaching 15 nH inductors, for example, the IC exhibited an insertion loss as low as 0.4 dB, an isolation of better than 40 dB at 1.5 GHz, a bandwidth of about 400 MHz for 20 dB isolation, and P_1dB of about 34 dBm with the 0/3 V control     

A 20 GHz Band 0.5 W GaAs FET Amplifier for Satellite Communications

GaAs FET amplifier modules for 20 GHz band satellite communications have been developed using newly developed power FETs. The deep recess gate structure was adopted in the power FET, which improved both power output capability and power gain. Power added efficiency of 22 percent with more than 1 W power output has been achieved with 3 mm gate width FETs. The amplifier modules containing two-stage internally matched FET's can be hermetically sealed in metal packages. The modules had 8.4-8.9 dB linear gain in the 17.7-18.8 GHz band and 7.9-8.4 dB linear gain in the 18.5-19.6 GHz band. The power output at 1 dB gain compression point was more than 0.5 W. The third-order intermodulation distortion ratio was 81-83 dB at 18.2 GHz and 77-80 dB at 18.9 GHz, when individual output signal power was -4 dBm.     

Low-power InP-HEMT switch ICs integrating miniaturized 2/spl times/2 switches for 10-Gb/s systems

This paper presents a wideband cold-FET switch with virtually zero power dissipation. The use of InP HEMTs with a low R/sub on//spl middot/C/sub off/ product enables us to configure a DC-to-over-10-GHz single-pole double-throw (SPDT) switch without using a shunt FET. The series-FET configuration offers a logic-level-independent interface and makes possible positive control voltage operation in spite of using depletion-mode FETs. A miniaturized 2/spl times/2 switch using two SPDT switches yields an insertion loss of less than 1.16 dB and isolation of more than 21.2 dB below 10 GHz, which allows us to increase the scale of the switch in a single chip easily. The add-drop operation combining two 2/spl times/2 switches in a single chip and a 4/spl times/4 switch IC integrating four 2/spl times/2 switches are presented. The packaged ICs achieve error-free operation up to 12.5 Gb/s with either positive or negative logic-level input. Extremely fast switching of /spl sim/140 ps is also successfully demonstrated.     

基于滤波器综合分析法的118 GHz单刀二掷开关

采用滤波器综合分析方法, 基于分立式AlGaAs/GaAs异质结PIN二极管, 根据其等效寄生参数, 综合出单刀二掷开关集总参数滤波器模型, 以此分析其等效分布参数电路, 设计出了118 GHz星载辐射计用单刀二掷开关准单片, 开关电路尺寸6×2.5×0.1 mm3.通过开关模块封装用波导-微带过渡和键合金带插损的分析研究, 研制出了低插损的118 GHz开关模块, 在110~120 GHz, 测得开关插损小于3.0 dB, 插损典型值2.6 dB;开关隔离度大于22 dB;开关响应时间、导通时间、关断时间、恢复时间分别小于18 ns、20 ns、10 ns、18 ns, 该准单片作为通道切换开关可集成应用于118 GHz收发组件中.     

Design and performance of a Ka-band monolithic phase shifterutilizing nonresonant FET switches

This paper describes design consideration and performance of a Ka-band monolithic phase shifter utilizing nonresonant FET switches. The switches show broad-band on/off characteristics up to 60 GHz without using inductors; thus, robust circuit design is possible for a switched-line phase shifter. To determine circuit topology, we introduce a schematic design approach. As a result, desired phase shift as well as good matching characteristics can be realized. The developed 4-bit monolithic phase shifter demonstrates an overall phase deviation less than 5° rms and an insertion loss variation less than 0.65 dB rms from 33 to 35 GHz. For all 16 states, the insertion loss is measured to be 13.1±1.1 dB and the VSWR is less than 1.6. The chip size of the monolithic phase shifter is 2.5 mm×2.2 mm     

Low-noise two-dimensional electron gas FET

Two-dimensional electron gas FETs (TEGFETs) have been fabricated on an N-AlGaAs-GaAs heterojunction. Microwave results at 10 GHz are: NF=2.3 dB, Gass=10.3 dB and Gmax=13.2 dB. These first results obtained on nonoptimised material and processing suggest that TEGFET can be superior to a conventional GaAs FET.     

DC-110-GHz MMIC traveling-wave switch

This paper presents the broadest band monolithic-microwave integrated-circuit traveling-wave switch ever reported for millimeter-wave applications. The developed switch with the novel structure of a 400-μm-gate finger field-effect transistor (FET) indicated an insertion loss of less than 2.55 dB and an isolation of better than 22.2 dB from dc to 110 GHz. Also, the switch indicated no degradation of insertion loss and an ON/OFF ratio of more than 22.7 dB up to an input power of 26.5 dBm at 40 GHz. Circuit analytical results based on a lossy transmission-line model for small-signal performance and circuit simulation results using the two-terminal nonlinear FET model for large-signal operation successfully showed good agreement with the experimental results     

Resonated GaAs FET devices for microwave switching

Several designs of monolithic switches for X-band applications have been fabricated and tested. These switches, which consist of two parallel-resonated GaAs FET's in a series SPDT configuration, have very low dc power dissipation, low insertion loss, and are bidirectional. An insertion loss of 0.7 dB with 28-dB isolation at 10.2 GHz has been measured for these devices. A simple equivalent circuit model is presented which explains reasonably well the basic features of resonated GaAs FET switches. The tradeoffs between performance and bandwidth, and the important design criteria, particularly with respect to the layout of monolithic inductors, are investigated.     

A high-performance 40-85 GHz MMIC SPDT switch using FET-integrated transmission line structure

A compact ultra-broadband distributed SPDT switch has been developed using GaAs PHEMTs. An FET-integrated transmission line structure, where the source pad of the shunt FET has been integrated into the signal line while the drain has been grounded to a via-hole with minimum parasitic inductance, has been proposed to extend the operating bandwidth of the distributed switches. SPDT and SPST switches using this structure have been fabricated using a commercial GaAs PHEMT foundry. The SPDT switch showed low insertion loss (<2 dB) and good isolation (>30 dB) over an octave bandwidth from 40 to 85 GHz. At 77 GHz, the SPDT switch showed extremely low insertion loss of 1.4 dB and high isolation of 38 dB. The chip size was as small as 1.45/spl times/1.0 mm/sup 2/. To the best of our knowledge, this is among the best performance ever reported for an octave-band SPDT switch at this frequency range. SPST switch also showed the excellent performance with the insertion loss of 0.4 dB and isolation of 34 dB at 60 GHz.     

The package integration of RF-MEMS switch and control IC for wireless applications

The integration of microelectromechanical systems (MEMS) switch and control integrated circuit (IC) in a single package was developed for use in next-generation portable wireless systems. This packaged radio-frequency (RF) MEMS switch exhibits an insertion loss under -0.4 dB, and isolation greater than -45 dB. This MEMS switch technology has significantly better RF characteristics than conventional PIN diodes or field effect transistor (FET) switches and consumes less power. The RF MEMS switch chip has been integrated with a high voltage charge pump plus control logic chips into a single package to accommodate the low voltage requirements in portable wireless applications. This paper discusses the package assembly process and critical parameters for integration of MEMS devices and bi-complementary metal oxide semiconductor (CMOS) control integrated circuit (IC) into a single package.     

低噪声GaAs MESFET有源层的Si~+注入

本文叙述了用Si~+注入GaAs形成低噪声MESFET有源层的初步实验结果.获得了峰值载流子浓度为1～2×10(17)cm~(-3)、在交界面处迁移率≥3000cm~2/V·s的有源层,制出了在2GHz下NF为0.9dB、G_a为14.5dB的双栅FET和9.5GHz下NF为2.0dB、G_a为9.5dB的单栅FET.实验结果表明,采用Si~+注入沟道的器件达到了汽相外延器件的最佳性能,某些参数超过了汽相外延器件.     

高隔离度S波段MEMS膜桥开关

常规的 MEMS膜桥开关在 1 0 GHz以上频段才具有低插损、高隔离度 (>2 0 d B)的优点。文中介绍了一种应用于微波低频段—— S波段的高隔离 MEMS膜桥开关 ,给出了开关的设计与优化方法 ,建立了开关的等效电路模型。通过双膜桥结构、选择高介电常数的介质膜、微电感结构膜桥这些措施 ,达到提高开关隔离度的目的。利用 HFSS软件仿真的结果表明 ,该开关在微波低频段 (3～ 6GHz)有着很好的隔离性能。开关样品在片测试的电性能指标 :插损 <0 .3 d B,隔离度 >40 d B,驱动电压 <2 0 V     

Fabrication, assembly, and testing of RF MEMS capacitive switches using flexible printed circuit technology

A novel approach for cost effective fabrication, assembly, and packaging of radio-frequency microelectromechanical systems (RF MEMS) capacitive switches using flexible circuit processing techniques is reported. The key feature of this approach is the use of most commonly used flexible circuit film, Kapton-E polyimide film, as the movable switch membrane. The physical dimensions of these switches are in the mesoscale range. For example, electrode area and gap height of a capacitive shunt switch on coplanar waveguide are 2 /spl times/ 1 mm/sup 2/ and 43 /spl mu/m, respectively. Pull-down voltage is in the range of 90-100 V. In the ON state (up-position), the insertion loss is less than 0.3-0.4 dB up to 30 GHz. In OFF state (down-position), the isolation value is about 15 dB at 12 GHz and increases to 36 dB at 30 GHz. These switches are uniquely suitable for batch integration with printed circuits and antennas on laminate substrates.     

20 GHz band high-power onboard beam-switching circuit for multibeam satellite systems

A newly developed K-band beam-switching circuit is presented. The experimental SPDT switching circuit has a high-power handling capability of more than 10 W, low insertion loss of less than 1.2 dB, high isolation of more than 23 dB and a high-speed switching time of faster than 100 ns in the frequency band between 18.85 and 19.15 GHz.     

RF MEMS开关的设计分析

针对具有低损耗、高隔离度性能的微机电系统(Micro-Electro-Mechanical System,MEMS)开关,介绍了串联DC式和并联电容式的开关结构模型,并对并联电容式MEMS开关的工作原理、等效电路模型和制造工艺流程进行了描述,利用其模型研究了开关的微波传输性能,设计了一款电容耦合式开关并进行了仿真。由仿真结果可得,开关"开态"时的插入损耗在40 GHz以内优于-0.3 dB;开关"关态"时的隔离度在20～40 GHz相对较宽的频带内优于-20 dB。     

RF performance of diamond MISFETs

A cutoff frequency (f_T) of 11 GHz is realized in the hydrogen-terminated surface channel diamond metal-insulator-semiconductor field-effect transistor (MISFET) with 0.7 μm gate length. This value is five times higher than that of 2 μm gate metal-semiconductor (MES) FETs and the maximum value in diamond FETs at present. Utilizing CaF₂ as an insulator in the MIS structure, the gate-source capacitance is reduced to half that of the diamond MESFET because of the gate insulator capacitance being in series to the surface-channel capacitance. This FET also exhibits the highest f _max of 18 GHz and 15 dB of power gain at 2 GHz. The high-frequency equivalent circuits of diamond MISFET are deduced from the S-parameters obtained from RF measurement     

Extraction techniques for FET switch modeling

A new simple method for extracting equivalent circuit parameters for series and shunt GaAs FET switches is presented. The circuit elements are extracted from one set of S-parameter measurements for each switch state, and scale linearly with gate width. Extracted Equivalent Circuit Parameters (ECP's) are insensitive to frequency across the measured bandwidth. Good agreement has been obtained between simulated and model results for a 0.5 μm gate length series and shunt GaAs FET switches of varying gate widths, across the 0.45-26.5 GHz band