宽带小型化微带均衡器设计

功率放大模块在工作频带内存在增益波动的情况,目前较为理想的解决方案是在原传输网络中添加一个增益均衡网络,该均衡网络就是增益均衡器。文章针对2~6 GHz 功放模块增益波动较大的问题,设计和制造了一种采用微带电路的小型化均衡器,其工作频率为2~6 GHz,均衡量约为9 dB,输入输出驻波系数小于1.5,改善了功放模块输出功率不平坦的问题,对研发该类均衡器有一定的参考价值。文中简要介绍了传输线和增益均衡器的基本原理以及薄膜电路的相关设计,结合实际需求,确定目标曲线,设计增益均衡器的初始模型,再利用三维场仿真软件对增益均衡器进行仿真优化,研制出2~6 GHz 微带型增益均衡器。该增益均衡器实测结果与设计基本吻合,满足了小型化的设计要求。     

AlGaN-GaN HEMTs on SiC with CW power performance of >4 W/mm and 23% PAE at 35 GHz

In this work, continuous wave Ka-band power performance of AlGaN-GaN high electron-mobility transistors grown on semi-insulating SiC substrates are reported. The devices, with gate lengths of 0.25 /spl mu/m, exhibited maximum drain current density of 1.1 A/mm and peak extrinsic transconductance of 285 mS/mm. At 35 GHz, an output power density of 4.13 W/mm with 23% of power-added efficiency (PAE) and 7.54 dB of linear gain were achieved at a drain bias of 30 V. These power results represent the best power density, PAE, and gain combination reported at this frequency. The drain bias dependence of the Ka-band power performance of these devices is also presented.     

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.     

微波高功率双介质栅静电感应晶体管

提出了用同步外延法设计和制造具有双介质层栅结构和非饱和电流电压特性的高频高功率静电感应晶体管的关键技术.讨论了寄生栅源电容Cgs对静电感应晶体管高频功率特性的影响.描述了工艺上减小寄生电容、改善静电感应晶体管高频功率性能的主要方法和措施.成功地制造出频率在400MHz时输出功率大于20W、功率增益大于7dB、漏效率大于70%和700MHz时输出功率大于7W、功率增益大于5dB,漏效率大于50%的高性能静电感应晶体管.     

Automated Test Equipment for Phased-Array Modules

A computer-controlled production test system for air-borne phased-array microwave modules is described. In the transmit mode accurate measurements of module output power and phase as a function of input power and frequency are made automatically on a pulse basis, and with 4:1 frequency translation from module input to output. Module receiver gain, IF output phase, and noise figure are measured as a function of frequency and local oscillator input power in the receive mode. Other measurements under computer control include dc levels, input and output VSWRS, gain compression, output pulse characteristics, spurious levels, and spectral purity. All test parameters are automatically compared to unit-specification limits as well as reference-standard (unit-to-unit) limits. The system errors are measured periodically through use of calibration standards, stored in memory, and applied as corrections to the measured data on the module under test. Input power, derived from a coherent microwave synthesizer, is automatically adjusted to the required level prior to each test. All test data are recorded on magnetic tape and available to the operator by means of a line printer when desired. The module test fixture incorporates precision (APC)-7 to module adapters, dc connections, an array simulator, and temperature control.     

High DC and microwave characteristics of subhalf-micrometre gate ion-implanted GaAs MESFETs using trilayer deep UV lithography

Subhalf-micrometre gate length ion-implanted GaAs MESFETs have been fabricated on 3 inch diameter substrates using trilayer deep UV lithography. Implanted MESFETs with 0.3 mu m gate lengths exhibit a maximum extrinsic transconductance of 205 mS/mm at a drain current of 600 mA/mm. From S-parameter measurements, a current gain cutoff frequency f/sub t/ of 56 GHz and a maximum available gain cutoff frequency f/sub max/ greater than 90 GHz are achieved. The gate-to-drain diode characteristics of the devices show a sharp breakdown voltage of 13-15 V. The high drain current-drain voltage and microwave characteristics indicate that ion-implanted technology with trilayer deep UV lithography has potential for the manufacture of power devices and amplifiers for Q-band communication applications. This is the first reported result using trilayer deep UV lithography to demonstrate both f/sub t/ over 56 GHz and 13-15 V gate-to-drain breakdown on 0.3 mu m gate-length ion-implanted GaAs MESFETs.<>     

On Theory and Performance of Solid-State Microwave Distributed Amplifiers

The performance characteristics of n-link distributed amplifiers employing GaAs MESFET'S are studied. At first, formulas of tie symmetrical amplifier using lumped circuit elements are developed for the case of an idealized FET model. The theoretical analysis is then extended to distributed line elements and later to an S-parameter derived transistor model. In efforts to optimize amplifier performance, the restriction of circuit symmetry is subsequently removed and the performance characteristics of two concepts, that of equal characteristic impedances and that of equal line lengths, are proposed and compared. Based on this analysis and practical considerations, several three-link hybrid amplifiers utilizing the equal line lengths approach have been assembled and test results are reported. A gain of G = 5.5+-0.6 dB was measured over the bandwidth of 2-20 GHz. Across this frequency band a maximum VSWR of 2.2:1 for the input and 2.5:1 for the output terminaf have been reafized, while a minimum output power at the l-dB compression points of 19.3 dBm was achieved from 2-18 GHz. Agreement between measured and computed small-signal gain as well as reverse isolation is excellent.     

Fabrication and characterization of AlGaN/GaN HEMTs with high power gain and efficiency at 8 GHz

State-of-the-art AlGaN/GaN high electron mobility structures were grown on semi-insulating 4H-SiC substrates by MOCVD and X-band microwave power high electron mobility transistors were fabricated and characterized.Hall mobility of 2291.1 cm2/(V·s) and two-dimensional electron gas density of 9.954 × 1012 cm-2 were achieved at 300 K.The HEMT devices with a 0.45-μm gate length exhibited maximum drain current density as high as 1039.6 mA/mm and peak extrinsic transconduct-ance of 229.7 mS/mm.The fT of 30.89 GHz and fmax of 38.71 GHz were measured on the device.Load-pull measurements were performed and analyzed under (-3.5,28) V,(-3.5,34) V and (-3.5,40) V gate/drain direct current bias in class-AB,respectively.The uncooled device showed high linear power gain of 17.04 dB and high power-added efficiency of 50.56％ at 8 GHz when drain biased at (-3.5,28) V.In addition,when drain biased at (-3.5,40) V,the device exhibited a saturation output power dens-ity up to 6.21 W/mm at 8 GHz,with a power gain of 11.94 dB and a power-added efficiency of 39.56％.Furthermore,the low fmax/fT ratio and the variation of the power sweep of the device at 8 GHz with drain bias voltage were analyzed.     

单片行波功率放大器

报道了一个单片行波功率放大器的研究结果。单级放大器电路采用6个栅宽为420μn的GaAsMESFET作为有源器件，通过采用栅串联电容和漏线阻抗渐变技术，在（1-13）GHz频率范围内线性增益为7．5±0．5dB，输出功率大于0．5W，功率附加效率为16％，输入输出驻波比在1．2—2，1之间。采用离子注入、背面通孔等先进工艺制作在厚度为0．1mm的GaAs基片上，芯片面积为3．7mm×1．85mm。将两个这样的芯片级联得到13±1dB的线性增益。     

A $K$ -Band CMOS Distributed Doubler With Current-Reuse Technique

A $K$-band distributed frequency doubler is developed in 0.18 $mu{rm m}$ CMOS technology. This doubler combines the distributed topology for broadband characteristics and current-reuse technique to improve the conversion gain. The high-pass drain line and high-pass inter-stage matching network are used to obtain a good fundamental rejection. A measured conversion gain of better than ${- 12.3}~{rm dB}$ is obtained, and the fundamental rejection is better than 30 dB for the output frequency between 18 and 26 GHz. The dc power consumption is 10.5 mW with a chip size of 0.55$,times,$0.5 ${rm mm}^{2}$.      

Indium gallium arsenide microwave power transistors

Depletion-mode InGaAs microwave power MISFETs with 1-μm gate lengths and up to 1-mm gate widths have been fabricated using an ion-implanted process. The devices employed a plasma-deposited silicon/silicon dioxide gate insulator. The DC current-voltage (I -V) characteristics and RF power performance at 9.7 GHz are presented. The output power, power-added efficiency, and power gain as a function of input power are reported. An output power of 1.07 W at 9.7 GHz with a corresponding power gain and power-added efficiency of 4.3 dB and 38%, respectively, was obtained. The large-gate-width devices provided over twice the previously reported output power for InGaAs MISFETs at X-band. In addition, the first report of RF output stability of InGaAs MISFETs over 24 h period is also presented. An output power stability within 1.2% over 24 h of continuous operation was achieved. In addition, a drain current drift of 4% over 10⁴ s was obtained     

An X-band four-way combined GaN solid-state power amplifier

An X-band four-way combined GaN solid-state power amplifier module is fabricated based on a self-developed AlGaN/GaN HEMT with 2.5-mm gate width technology on SiC substrate. The module consists of an Al-GaN/GaN HEMT, Wilkinson power hybrids, a DC-bias circuit and microstrip matching circuits. For the stability of the amplifier module, special RC networks at the input and output, a resistor between the DC power supply and a transistor gate at the input and 3λ/4 Wilkinson power hybrids are used for the cancellation of low frequency self-oscillation and crosstalk of each amplifier. Under V_(ds)= 27 V, V_(gs) = -4.0 V, CW operating conditions at 8 GHz, the amplifier module exhibits a line gain of 5 dB with a power added efficiency of 17.9%, and an output power of 42.93 dBm; the power gain compression is 2 dB. For a four-way combined solid-state amplifier, the power combining efficiency is 67.5%. It is concluded that the reduction in combining efficiency results from the non-identical GaN HMET, the loss of the hybrid coupler and the circuit fabricating errors of each one-way amplifier.     

Gallium-arsenide E- and D-MESFET device noise characteristicsoperated at cryogenic temperatures with ultralow drain current

The low-frequency noise characteristics of GaAs MESFETs operating at very low power and at cryogenic temperatures of 77 and 10 K as well as at room temperature are discussed. A self-aligned gate and a buried p-layer were incorporated to maximize device gain and minimize low-frequency noise. Measurements at 77 K show a noise voltage spectral density of 1.0-2.0 μV/√Hz at 1.0 Hz (referred to the transistor input) with a drain current of 1.0 μA     

一种基于锥形微带线的宽带F 类功率放大器

提出了一种基于5G 频段的宽带高效率F 类功率放大器。分析表明锥形微带线可以有效解决矩形微带线对于带宽的限制问题, 同时将锥形微带线加入谐波控制网络, 可以实现在一定频率范围内将二次谐波阻抗匹配至短路点附近, 三次谐波阻抗匹配至开路点附近, 从而有效解决了F 类功率放大器带宽和效率的问题。使用锥形微带线制作的功放, 实测结果表明: 在2.7 ~3.8GHz 的频带范围内, 漏极效率达到63% ~78%, 平均输出功率达到10W以上, 大信号增益达到10dB 以上。在5G 无线通信中, 该功放可以有效地发挥其宽带高效率的特点。     

AlGaN/GaN HEMTs with 0.2μm V-gate recesses for X-band application

正AlGaN/GaN HEMTs with 0.2μm V-gate recesses were developed.The 0.2μm recess lengths were shrunk from the 0.6μm designed gate footprint length after isotropic SiN deposition and anisotropic recessed gate dry etching.The AlGaN/GaN HEMTs with 0.2μm V-gate recesses on sapphire substrates exhibited a current gain cutoff frequency f_t of 35 GHz and a maximum frequency of oscillation f_(max) of 60 GHz.At 10 GHz frequency and 20 V drain bias,the V-gate recess devices exhibited an output power density of 4.44 W/mm with the associated power added efficiency as high as 49%.     

Gate-controlled negative differential resistance in drain currentcharacteristics of AlGaAs/InGaAs/GaAs pseudomorphic MODFETs

The observation of negative differential resistance (NDR) and negative transconductance at high drain and gate fields in depletion-mode AlGaAs/InGaAs/GaAs MODFETs with gate lengths L _g ~0.25 μm is discussed. It is shown that under high bias voltage conditions, V_ds>2.5 V and V_gs>0 V, the device drain current characteristic switches from a high current state to a low current state, resulting in reflection gain in the drain circuit of the MODFET. The decrease in the drain current of the device corresponds to a sudden increase in the gate current. It is shown that the device can be operated in two regions: (1) standard MODFET operation for V_gs<0 V resulting in f_max values of >120 GHz, and (2) a NDR region which yields operation as a reflection gain amplifier for V_gs >0 V and V_ds>2.5 V, resulting in 2 dB of reflection gain at 26.5 GHz. The NDR is attributed to the redistribution of charge and voltage in the channel caused by electrons crossing the heterobarrier under high-field conditions. The NDR gain regime, which is controllable by gate and drain voltages, is a new operating mode for MODFETs under high bias conditions     

The Matrix Amplifier: A High-Gain Module for Multioctave Frequency Bands

The characteristics of a new type of amplifier that makes simultaneous use of the additive and the multiplicative amplification process in one and the same module is discussed. The device, which achieves high-gain performance over multioctave bands, is a relative of the distributed amplifier. Initial experimental results demonstrated a small-signal gain of G = 13.8+-0.8 dB with -11.4 dB of maximum return loss between 2.0 and 21.5 GHz when using MESFET's manufactured on ion-implanted substrate material and G = 16.8+-0.9 dB gain over the 2.3-20.3-GHz frequency band in the case of vapor-phase-epitaxiaI material. The principle, the theory, and the experimental results are discussed in detail.     

108 GHz 功率放大器模块研制

介绍了105～108 GHz 频段功率放大器模块的设计和制作。模块由波导微带转换、功率芯片及芯片偏置电路组成。讨论了放大模块的设计及加工测试过程,并对模块中的关键技术波导-微带转换进行详细阐述。波导-微带转换采用E面微带探针激励完成。通过理论分析及仿真优化后设计出转换模型并制作出实物进行测试。单个转换在100～110GHz 频段内插入损耗小于0.6 dB,回波小于-10 dB。测试结果表明设计的波导-微带转换具有插入损耗小,工作频段宽的优点。采用此转换制作的功率放大模块在105～108GHz频段上增益大于13dB,输出功率大于200mW,达到预期设计指标。     

14.5～15GHz11W内匹配功率器件

介绍了一种采用GaAs PHEMT管芯设计的超高频内匹配功率器件。为了在更高的频率获得较高的输出功率,采用0.25μm栅长的PHEMT工艺,制作了总栅宽19.2 mm的大功率管芯。采用频带较宽的微带渐变传输线和T型网络共同组成栅极和漏极的匹配电路,并对封装管壳进行优化,有效提高了器件的微波特性。在带内频率14.5～15 GHz、漏源电压Vds为8 V时,器件输出功率大于40.4 dBm(11 W),线性功率增益为7 dB,功率附加效率大于23%。     

3cm-T/R组件的研制

介绍了一种3cm-T/R组件的设计与制作,该组件基于LTCC技术,运用两只功率放大器裸芯片和一个Wilkinson功分合成器设计出了一个平衡放大器,并且作为3cm-T/R组件发射通道的末级功放.文章分析了收发组件的原理方案,详细讨论了电磁兼容问题和装配工艺,充分利用了混合集成电路(HMIC)和多芯片组装(MCM)相结合...