工作在1.8-3 GHz内的高效率GaAs pHEMT功率单片

本文报道了一款基于南京电子器件研究所GaAs pHEMT单片集成电路工艺的S波段宽带高效率功率放大器。为了提高芯片效率,该放大器采用驱动比为1:8的两级级联方式,并采用低通/高通滤波器相结合的拓扑结构设计每级的匹配电路。这种匹配电路在有效降低芯片面积的同时,在较宽的频带范围内实现对应于高效率的阻抗匹配。在5V漏压AB类偏置条件下,该功率放大器在1.8到3GHz频率范围内连续波输出饱和功率为33~34 dBm,相应的附加效率达到35%~45%,以及非常平坦的功率增益25~26 dB。芯片面积紧凑,尺寸仅为2.7mm×2.75mm。     

A 15 Gbps-NRZ,30 Gbps-PAM4,120 mA laser diode driver implemented in 0.15-an GaAs E-mode pHEMT technology

This paper presents the design and testing of a 15 Gbps non-return-to-zero (NRZ),30 Gbps 4-level pulse amplitude modulation (PAM4) configurable laser diode driver (LDD) implemented in 0.15-μm GaAs E-mode pHEMT technology.The driver bandwidth is enhanced by utilizing cross-coupled neutralization capacitors across the output stage.The output transmission-line back-termination,which absorbs signal reflections from the imperfectly matched load,is performed passively with on-chip 50-Ω resistors.The proposed 30 Gbps PAM4 LDD is implemented by combining two 15 Gbps-NRZ LDDs,as the high and low amplification paths,to generate PAM4 output current signal with levels of 0,40,80,and 120 mA when driving 25-Ω lasers.The high and low amplification paths can be used separately or simultaneously as a 15 Gbps-NRZ LDD.The measurement results show clear output eye diagrams at speeds of up to 15 and 30 Gbps for the NRZ and PAM4 drivers,respectively.At a maximum output current of 120 mA,the driver consumes 1.228 W from a single supply voltage of-5.2 V.The proposed driver shows a high current driving capability with a better output power to power dissipation ratio,which makes it suitable for driving high current distributed feedback (DFB) lasers.The chip occupies a total area of 0.7 × 1.3 mm2.     

A wide range,high yield and good performance pHEMT switch for MMIC phase shifter

A low-cost method with high yield and good performance is presented by pHEMTs (pseudomorphic high electron mobility transistors) to be used in phase shifter switches. In this method, the capacitor in “off” mode (C_off) of transistor is reduced, without variation of the transistor structure. The transistor structure in switch mode can be optimised. This method increases the transistor isolation in turn “off” mode, while there is no change in resistance of the transistor in “on” mode (R_on). Transistor dimension is determined in turn “off” mode (V_g = ?4.5 V) and standard form of 4 × 75 μm. So, in this method, insertion loss will be reduced without a perceptible change in transistor dimension. Thus, design and fabrication capability of some circuits such as phase shifters, antenna switches, SPDT (single port double throw) – without any change in technology – are increasing. In this paper, post layout and measurement result for a sample block of phase shifter are shown.     

New soft switching techniques for three phase voltage source inverters

Three new composite soft switching configurations for power inverters are presented. Each configuration incorporates an inductor to limit switch di/dt and diode reverse recovery current at turn-on, and realizes zero current switching at turn-off, with minimum active devices or passive components. Different features and applications of the configurations are considered. Simulations of three different inverter configurations are performed using PSpice and circuit switching waveforms are given, and experimental results confirmed analysis and simulations.     

Epitaxial Layer Design for High Performance GaAs pHEMT SPDT MMIC Switches

From a hydrodynamic device simulation for the pseudomorphic high electron mobility transistors (pHEMTs), we observe an increase of maximum extrinsic transconductance and a decrease of source-drain capacitances. This gives rise to an enhancement of the switching speed and isolation characteristics as the upper-to-lower planar-doping ratios (UTLPDR) increase. On the basis of simulation results, we fabricate single-pole-double-throw transmitter/receiver monolithic microwave integrated circuit (MMIC) switches with the pHEMTs of two different UTLPDRs (4:1 and 1:2). The MMIC switch with a 4:1 UTLPDR shows about 2.9 dB higher isolation and approximately 2.5 times faster switching speed than those with a 1:2 UTLPDR.     

宽带GaAs MMIC开关耦合器芯片设计

介绍了一种宽带开关耦合器芯片的研制。在GaAs pHEMT工艺平台上将宽带单刀双掷开关和兰格耦合器集成在一个芯片上,在实现二路功率分配功能的同时,还提供了在两个输出端口之间±90°相位切换的功能。该芯片频率范围覆盖6~18GHz,在整个频带内插入损耗<3.7dB,相位误差<14°,输入输出驻波比<1.8∶1。芯片尺寸1.5mm×3.0mm×0.1mm。详细描述了电路的设计流程,并提供最终的测试结果。该芯片具有频带宽、体积小、使用方便等特点,可应用于不同的微波系统。     

A Ka-band low-noise amplifier with a coplanar waveguide (CPW) structure with 0.15-μm GaAs pHEMT technology

This investigation explores a low-noise amplifier (LNA) with a coplanar waveguide (CPW) structure, in which a two-stage amplifier is associated with a cascade schematic circuit, implemented in 0.15-μm GaAs pseudo-morphic high electron mobility transistor (pHEMT) technology in a Ka-band (26.5-40.0 GHz) microwave monolithic integrated circuit (MMIC). The experimental results demonstrate that the proposed LNA has a peak gain of 12.53 dB at 30 GHz and a minimum noise figure of 3.3 dB at 29.5 GHz, when biased at a V_(ds) of 2 V and a V_(gs) of-0.6 V with a drain current of 16 mA in the circuit. The results show that the millimeter-wave LNA with coplanar waveguide structure has a higher gain and wider bandwidth than a conventional circuit. Finally, the overall LNA characterization exhibits high gain and low noise, indicating that the LNA has a compact circuit and favorable RF characteristics. The strong RF character exhibited by the LNA circuit can be used in millimeter-wave circuit applications.     

GaAs pHEMT工艺6～18GHz有源倍频器MMIC

基于GaAs pHEMT工艺,设计了一个6～18 GHz宽带有源倍频器MM IC,最终实现了较高的转换增益和谐波抑制特性。芯片内部集成了输入匹配、有源巴伦、对管倍频器和输出功率放大器等电路。外加3.5 V电源电压下的静态电流为80 mA;输入功率为6 dBm时,6～18 GHz输出带宽内的转换增益为6 dB;基波和三次谐波抑制30 dBc。当输出频率为12 GHz时,100 kHz频偏下的单边带相位噪声为-143 dBc/Hz。芯片面积为1 mm×1.5 mm。     

Design of a 24–40 GHz balanced low noise amplifier using Lange couplers

A wide band （24–40 GHz） fully integrated balanced low noise amplifier （LNA） using Lange couplers was designed and fabricated with a 0.15 μm pseudomorphic HEMT （pHEMT） technology. A new method to design a low-loss and high-coupling Lange coupler for wide band application in microwave frequency was also presented. This Lange coupler has a minimum loss of 0.09 dB and a maximum loss of 0.2 dB over the bandwidth from 20 to 45 GHz. The measured results show that the realized four-stage balanced LNA using this Lange coupler exhibites a noise figure （NF） of less than 2.7 dB and the maximum gain of 30 dB; moreover, a noticeably improved reflection performance is achieved. The input VSWR and the output VSWR are respectively less than 1.45 and 1.35 dB across the 24–40 GHz frequency range.     

Ku-Band Power Amplifier MMIC Chipset with On-Chip Active Gate Bias Circuit

We propose a Ku-band driver and high-power amplifier monolithic microwave integrated circuits (MMICs) employing a compensating gate bias circuit using a commercial 0.5 μm GaAs pHEMT technology. The integrated gate bias circuit provides compensation for the threshold voltage and temperature variations as well as independence of the supply voltage variations. A fabricated two-stage Ku-band driver amplifier MMIC exhibits a typical output power of 30.5 dBm and power-added efficiency (PAE) of 37% over a 13.5 GHz to 15.0 GHz frequency band, while a fabricated three-stage Ku-band high-power amplifier MMIC exhibits a maximum saturated output power of 39.25 dBm (8.4 W) and PAE of 22.7% at 14.5 GHz.