X-band MIC GaAs IMPATT amplifier module

A compact (2.0 by 1.6 in), light weight (2.1 oz), microwave integrated circuit (MIC) GaAs IMPATT amplifier module having 3.6-W pulsed output power with a gain of 22.5 dB over the 9.2-9.8 GHz band has been developed for phased array radar applications. The design goal for the module was 4-W pulsed output power with 23-dB gain over this frequency band. The module has been operated over a wide range of pulse lengths (200 ns-50 /spl mu/s) and duty factors (0.5-40 percent) with outstanding pulse fidelity. The totally integrated module consists of three IMPATT reflection amplifier stages in cascade with input and output isolators and a transmit/receive switch. Each amplifier stage has an independent hybrid thin film constant current pulse modulator. The design considerations of the essential components for final module integration, and the microwave performance characteristics are presented.     

一种用于微波系统的输入电压控制电路

随着射频技术的不断发展,微波系统对功率密度、可靠性的重视程度不断提高。以氮化镓为基础的微波功率器件的应用取得了很大的进步,对微波系统的供电时序也提出了更高要求。根据微波系统对脉冲电压及电源时序控制的要求,设计了一种电压控制电路,实现直流输入电压的脉冲输出和上电、掉电时序的控制,并通过实验电路对设计原理进行了验证。     

基于状态机控制的降压型开关电容DC-DC转换器

介绍一种基于状态机控制的多种增益模式转换的控制方法,采用增益跳变和跳周期调制技术,控制增益模式的切换和开关频率,使输出电压稳定,并使系统有较高的转换效率。基于csmc0.5 μm CMOS工艺进行spectreverilog[JP]仿真,结果表明能准确控制3种增益的切换和开关频率的变化,并可输出约1.8 V的稳定电压,纹波＜20 mV,达到了预期目的。     

Power performance and scalability of AlGaN/GaN power MODFETs

The scalability of power performance of AlGaN/GaN MODFETs with large gate periphery, as necessary for microwave power devices, is addressed in this paper. High-frequency large-signal characteristics of AlGaN/GaN MODFETs measured at 8 GHz are reported for devices with gatewidths from 200 μm to 1 mm. 1-dB gain compression occurred at input power levels varying from -1 to +10 dBm as the gatewidth increased, while gain remained almost constant at -17 dB. Output power density was ~1 W/mm for all devices and maximum output power (29.9 dBm) occurred in devices with 1-mm gates, while power-added efficiency remained almost constant at ~30%. The large-signal characteristics were compared with those obtained by dc and small-signal S-parameters measurements. The results illustrate a notable scalability of AlGaN/GaN MODFET power characteristics and demonstrate their excellent potential for power applications     

W波段集成化收发组件设计北大核心CSCD

基于混合微波集成电路技术(HMIC)设计了一种W波段小型化高频收发组件。该收发组件由固态发射机、环形器和接收机三部分组成。发射支路输入信号经过倍频放大后进入二选一开关,输出到天线自检口或经由环形器输出。为了实现高输出功率,该组件采用功率合成的设计思想,通过3 dB波导桥结构实现对两路功放的合成,解决了单个单片功率放大器的输出功率有限的问题。所设计的收发组件整体尺寸为125 mm×90 mm×26.5 mm。实测结果表明,在90~96 GHz工作频带范围内,遥测电压4.23 V。该收发组件的发射部分输出功率范围为33.6~35.4 dBm,开关隔离度大于110 dB;接收部分增益范围为30.2~33 dB,噪声系数小于6.5 dB。该组件具备良好的射频性能,同时实现了高集成度、大功率、高增益、高隔离度的要求。     

双包层Er3 + /Yb3 + 共掺光纤放大器动态特性研究

基于速率方程的离散算法，实现了对双包层Er^3＋／Yb^3＋光纤放大器动态特性的分析。研究了不同信号和泵浦功率下单信道的瞬态功率、脉冲序列输出功率与增益随时间的变化以及多信道异步转移模式下输出功率和增益随时间的变化。结果表明：对于单个脉冲，在相同的泵浦功率下，输出脉冲的峰值功率取决于输入脉冲的峰值功率；在不同的泵浦功率下，输出脉冲的峰值功率取决于泵浦功率。对于脉冲序列，在达到稳定的输出前，将经历一个输出功率和增益由高到低的变化过程。对于异步转移模式的多信道脉冲，脉冲重叠时的功率和增益变化要快于非重叠时功率和增益的变化。     

超宽带延时幅相控制多功能芯片的设计

针对航空航天和卫星通信等设备的需求,介绍了一款超宽带延时幅相控制多功能芯片。该芯片集成了数字和微波电路,有T/R 开关、5 位数控延时器(10 ps 步进TTD)、5位数控衰减器(1 dB 步进ATT)、2 个行波放大器、均衡器及数字电路。基于GaAs E/D PHEMT 工艺研制出了芯片实物,芯片尺寸为4.5 mm*5.0 mm*0.07 mm。采用微波在片测试系统对该幅相控制多功能芯片进行了实际测试,在3 ~ 17 GHz 频段内实现了10~310 ps 延时范围,1~31 dB 衰减范围。测试结果显示,发射/接收增益大于2 dB,发射1 dB 压缩输出功率P1 dB_Tx大于12 dBm,接收1 dB 压缩输出功率P1 dB_Rx大于10 dBm,全态输入输出驻波均小于1.7,+5 V 下工作电流130 mA,-5 V 下工作电流12 mA。衰减器全态RMS 精度小于1.4 dB,全态附加调相小于±8°。延时器全态RMS 精度小于3 ps,全态附加调幅小于±1 dB。     

强流脉冲电子束特性对相对论速调管相位的影响分析

相位特性是强流相对论速调管放大器(RKA)的一个重要特征参数,而由高功率脉冲功率源产生的具有一定前沿的强流相对论电子束在驱动RKA时,会使得输出微波出现较大波动,影响RKA的输出微波相位稳定性及其应用.论文从强流脉冲电子束前沿分布状态出发,理论分析电子束前沿束流能量变化及其激励的腔体杂频对输出相位的影响,同时开展粒子模拟研究以及实验研究.研究结果表明:脉冲前沿段电子束能量变化将导致输出微波相位持续变化;此外,电子束前沿将激励杂模,导致输出微波相位在脉冲前沿段及平顶段初期持续抖动,在腔体参数一定条件下,脉冲前沿能量变化率越大,相位波动幅值越大,持续时间越长,通过减小杂频振荡频率处腔体的Q值可以有效缩短输出相位抖动时间,提高输出相位稳定性.     

11.GHz GaAs Power MESFET Load-Pull Measurements Utilizing a New Method of Determining Tuner Y Parameters

A Ioad-pull technique utilizing a new method of determining tuner Y parameters is proposed for huge-signal characterization of microwave power transistors. Large-signal input-output transfer characteristics of an active circuit containing a GaAs FET and an input matching circuit are measured by inserting a microstrip tuner between the active circuit output drain terminal and the 50-Omega load. The microstrip-tuner Y parameters are determined by comparing the dc bias-dependent small-signal S parameter S/sub 22/ of the active circuit and that of the circuit which contains the active circuit and microstrip tuner. The reflection coefficient presented to the active circuit output drain terminal is derived from tuner Y parameters. Optimal load impedances for output power, obtained with this new Ioad-pull technique, are used to design X-band GaAs FET power amplifiers. An 11-GHz power amplifier with a 3000-mu m gate-width FET chip delivers 1-W microwave power output with 4-dB gain in the 500-MHz band.     

Microwave power double-heterojunction HEMT's

The RF and dc characteristics of microwave power double-heterojunction HEMt's (DH-HEMT's) with low doping density have been studied. Small-signal RF measurements indicated that the cutoff frequency and the maximum frequency of oscillation in DH-HEMT's with 0.8-1 µm gate length and 1.2 mm gate periphery are typically 11- 16 GHz and 36-41 GHz, respectively. However, the cutoff frequency in DH-HEMT's degrades strongly with increasing drain bias voltage. This may be caused by both effects of increasing effective transit length of electrons and decreasing average electron velocity, due to Gunn domain formation. In large-signal microwave measurement, the DH-HEMT (2.4 mm gate periphery) delivered a maximum output power of 1.05 W with 2.8 dB gain and 0.58 W with 1.6 dB gain at 20 and 30 GHz, respectively. These are the highest output powers yet reported for HEMT devices. For the dc characteristics, the onset of two-terminal gate breakdown voltage is found to correlate with the drain current Idssand recessed length, and three-terminal source-drain breakdown characteristics near pinchoff are limited by the gate-drain breakdown. A simple model on gate breakdown voltage in HEMT is also presented.     

Nonlinearity in GaAs FET power amplifying devices

Modern microwave communication systems rely heavily on the linearity of output stages incorporating GaAs FET power amplifying devices. This letter describes a system for the automatic nonlinearity measurement in such devices of gain and phase angle as functions of input power level and frequency, with results leading to significantly improved system performance.     

The GaAs traveling-wave amplifier as a new kind of microwave transistor

A versatile solid-state microwave amplifier has evolved from a combination of transistor mechanisms and the transferred-electron effect. The prototype device, called a "traveling-wave transistor," employs a 2-µm layer of n-type GaAs grown epitaxially on a semi-insulating substrate. A transistor-like input launches a traveling space-charge wave that grows exponentially as it moves along the surface to a relatively distant output. There it is converted back into an electromagnetic wave. The long distance between input and output minimizes the feedback capacitance that often limits gain and bandwidth in high-frequency devices. Twelve experimental units show broad-band net gain in X band, with 10-30-dB built-in isolation. One unit exhibits instantaneous net gain from 6.7 to 15.3 GHz; another yields 28 dB at 9.2 GHz. All devices are good for linear microwave signal processing: voltage-controlled phase modulation at constant net gain, or voltage-controlled gain modulation at constant phase. Different bias conditions make possible threshold-sensitive saturated-amplitude amplification of pulses or sinusoids for logic or digital functions.     

UHF Integrated Power Amplifiers

This paper describes the development of integrated UHF power amplifiers using thin-film lumped elements and UHF power-transistor chips. Single-stage hybrid amplifier modules capable of delivering output powers up to 20 watts CW in the frequency range of 225-400 MHz are reported. In addition, broad-band hybrid amplifiers are discussed with 1-dB bandwidths of up to 40 percent in the same 225-400 MHz band. These amplifiers are presently housed in a three-terminal stud-mounted module, 0.8-inch high, 0.65-inch wide, and 0.35-inch deep. The module has a 50-ohm-impedance input lead, a 50-ohm-impedance output lead, and a dc lead (grounding is through the stud). Gain and output powers significantly greater than those available from a single module are obtained by cascading and/or paralleling individual modules at their 50-ohm terminals, either directly or by means of power combiners and power dividers. By use of the latter approach, a 76-watt amplitier having a gain of 15.8 dB at an operating frequency of 350 MHz has been constructed.     

GaAs m.e.s.f.e.t. linear power-amplifier stage giving 1 W

A balanced GaAs m.e.s.f.e.t. power stage has been developed for the 7?8 GHz satellite communication frequency band. At 7.5 GHz, the output power at 1 dB comparession 1 W with a power added efficiency of 37%. The small-signal gain was 6.65 ± 0.45 dB across the frequency band. The small-signal gain, phase, group delay and input and output v.s.w.r. as function of frequency are described. Large-signal gain saturation and 3rd-order intermodulation distrotion measurements are also presented.     

微波功率器件的扇形线测试电路

在微波电路原理和半导体器件物理的基础上,设计和模拟了两种用于微波功率器件的测试电路,并且设计了与之配套的测试夹具.采用矢量网络分析仪对该测试电路和夹具在3～8GHz范围内进行了小信号测试.模拟和测试结果都表明,采用扇形线的测试电路性能较好.最后采用该电路和夹具对C波段AlGaN/GaN HEMT微波功率器件进行了微波功率测试,测试频率为5.4GHz.实验测得最大功率增益为8.75dB,最大输出功率为33.2dBm.     

A Ku-BAND WAVEGUIDE FREQUENCY MULTIPLIER USING HARMONIC-REJECTION MICROSTRIP PATCH TRANSITIONS

A compact frequency multiplier waveguide module is built by placing a planar microstrip section between two rectangular waveguides. The size of the microstrip section is minimized by eliminating all harmonic band-rejection filters. Special feed locations for the input waveguide-to-microstrip transition patches provide the second-harmonic rejection at the input, and a balanced circuit configuration formed with a pair of transistors produces the pump signal cancellation at the output. The measurements on a fully-assembled waveguide module showed a peak frequency conversion gain of-2.3 dB at 16.7 GHz with the associated output power level of 6 dBm.     

微波功率器件的扇形线测试电路

在微波电路原理和半导体器件物理的基础上,设计和模拟了两种用于微波功率器件的测试电路,并且设计了与之配套的测试夹具.采用矢量网络分析仪对该测试电路和夹具在3～8GHz范围内进行了小信号测试.模拟和测试结果都表明,采用扇形线的测试电路性能较好.最后采用该电路和夹具对C波段AlGaN/GaN HEMT微波功率器件进行了微波功率测试,测试频率为5.4GHz.实验测得最大功率增益为8.75dB,最大输出功率为33.2dBm.     

A digitally controlled switch mode power supply based on matrix converter

High power telecommunication power supply systems consist of a three-phase switch mode rectifier followed by a dc/dc converter to supply loads at -48 V dc. These rectifiers draw significant harmonic currents from the utility, resulting in poor input power factor with high total harmonic distortion (THD). In this paper, a digitally controlled three-phase switch mode power supply based on a matrix converter is proposed for telecommunication applications. In the proposed approach, the matrix converter directly converts the low frequency (50/60Hz, three-phase) input to a high frequency (10/20kHz, one-phase) ac output without a dc-link. The output of the matrix converter is then processed via a high frequency isolation transformer to produce -48V dc. Digital control of the system ensures that the output voltage is regulated and the input currents are of high quality under varying load conditions. Due to the absence of dc-link electrolytic capacitors, power density of the proposed rectifier is expected to be higher. Analysis, design example and experimental results are presented from a three-phase 208-V, 1.5-kW laboratory prototype converter.     

Novel static inverters with high frequency pulse DC link

A novel combined soft switching technique and a novel topological family of the static inverter with high frequency pulse dc link are proposed in this paper. The topological structure is constituted of isolated high frequency pulse dc link circuit and inverter. In order to overcome the duty cycle D of the one transistor forward mode Static Inverter less than 0.5 and the topology of the interleaved forward mode Static Inverter more complicated, the duty cycle extension of high frequency pulse dc voltage is proposed in this paper. The steady operation principle of the active clamp forward mode high frequency pulse dc link static inverter with duty cycle extension and the control strategy of three-state discrete pulse modulation hysteresis current are deeply investigated. The design criteria for the key circuit parameters are gained. By using combined soft switching technique and the duty cycle extension of high frequency pulse dc voltage, a designed and developed 750 VA 27 V dc/115 V 400 Hz ac prototype has the advantages such as high efficiency, high power density, high reliability, high steady precision, fast dynamical response, low THD of output voltage, strong ability of over-load and short-circuit.     

E波段倍频放大模块设计

E波段是毫米波中非常重要的频段,也是较为缺乏研究的频段.E波段可三倍频至亚毫米波频段,其中220 GHz是大气吸收窗口,具有非常重要的研究价值.基于此,文中设计了一款E波段倍频放大模块,为220 GHz太赫兹发射机提供三倍频源信号,该模块输入频率为11.1～13.34 GHz,输出频率为66.6～80 GHz,输入功率...