Design And Research Of High Performance Millimeter-Wave MMIC Amplifier

With the increasing demand for high-speed wireless communication and the continuous progress of semiconductor technology,millimeter-wave technology has been developing rapidly,which has brought great changes to our life.It is predicted that millimeter-wave communication and its related applications will cover all aspects of our daily life.In addition to wireless communication,millimeter-wave technology also has a broad application prospect in radio astronomy,automobile assisted driving,medical detection and security imaging.As the compromise process between cost and performance of CMOS and InP technology,GaAs pHEMT（pseudomorphic high electron mobility transistor）has become the mainstream of commercial transceiver technology.A variety of high performance millimeter-wave amplifiers can be designed by combining GaAs process with millimeter-wave technology and relying on high performance devices.In this paper,the key circuits of the front end of high performance millimeter-wave receivers have been deeply studied,including the research and design of millimeter-wave ultra-wideband（UWB）low-noise amplifier（LNA）,the limiter-LNA and the wideband LNA with on-chip temperature-compensation circuit.The main research results are as follows.Firstly,the active and passive device models are analyzed and studied,and the small signal equivalent model is established for pHEMT devices to be used in the amplifiers.Small signal model parameters are extracted by using S parameters of different bias obtained from the test.Meanwhile,the fitting results are of high precision.The equivalent models of transmission lines,resistors,capacitors and planar spiral inductors are analyzed,thus,the passive device model is provided as accurate as possible for the design of amplifier circuits.The noise source in the LNA circuit and the pHEMT transistor noise model are studied.Meanwhile,the key indexes of the amplifier circuits,such as noise,gain,linearity and stability are analyzed and studied,which provide the foundation for the following circuits design.The bandwidth enhancement and noise reduction technique is studied in depth,and the multi-peaking bandwidth enhancement and noise reduction technique is proposed for the cascode topology to improve the performance of the LNA.In input matching,inter-stage matching,output matching and the RF choke bias circuit of the LNA,suitable inductors are added to expand the-3 dB bandwidth of the amplifier and reduce the noise figure（NF）.A five-octave UWB LNA is designed using this method.The test results show that the-3 dB bandwidth of the LNA is 1-32 GHz,the average small signal gain is 12.2 dB,the NF is1.9-2.6 dB,and the output-referred 1 dB compression point(OP_1dB)is 10.2-12.7 dBm,and the figure of merit（FOM）is 1.3.Among the monolithic integrated amplifiers（including on-chip bias networks）with the similar frequency bands reported in the same period,this UWB LNA has the lowest in-band room temperature NF and also has higher OP_1dB and FOM.The codesign method of PIN-diode limiter and low noise amplifier is studied.The theory of PIN diode,the principle and structure of the PIN limiter,the power-handling capability of the limiter and LNA are studied and analyzed.The improvement of PIN diode structure,the PIN-diode limiter structure and the LNA network are proposed,which can reduce the NF and chip area of the whole circuit without degrading the power-handling capability of the limiter-LNA.A Ka-band integrated PIN-diode based limiter-LNA is designed using this method.The test results show that in the 30-38 GHz band,the average small signal gain is17 dB with gain flatness of±0.6 dB,the NF is 2.2-2.6 dB with good input/output matching over the entire bandwidth,the power-handling capability is 38 dBm continuous wave（CW）input power.Compared with the Ka-band limiter/LNAs reported in the same period,this limiter-LNA demonstrates excellent performance including lower NF,higher tolerable power and smaller chip area.The temperature characteristics of transistors and amplifier circuits are studied in depth.Most of DC and small signal parameters show a negative trend with temperature,such as the drain current I_ds,the extrinsic transconductance g_m,the effective electron velocity v_effff and the threshold voltage V_th,resulting in a negative temperature-dependence of the gain of amplifier.Secondly,the reported temperature compensation technology of amplifier is analyzed.A precise temperature compensation network including two GaAs mesa resistors and two Nickel Chromium（Ni/Cr）thin-film resistors is proposed.The accurate temperature compensation is carried out at-55°C,25°C and 125°C,respectively.An UWB LNA MMIC with a simplified on-chip temperature-compensation circuit is designed.The test results show that the LNA has excellent temperature characteristics.The gain variation of the LNA is only 0.8 dB in the temperature range from-55°C to 125°C.To the best of our knowledge,it is the lowest the gain variation for UWB LNAs with temperature ever reported in the same period.The proposed temperature-compensated UWB-LNA can be further applied to automobiles,aircraft,instruments and space systems with complex working environment.In this paper,the design methods of UWB LNAs and two integrated functional amplifiers,namely the limiter-LNA and the temperature-compensated LNA,are described completely and in detail.The bandwidth enhancement and noise reduction technique for the UWB LNA,the noise reduction and miniaturization technique for the limiter-LNA,the high precision temperature-compensation technique for the amplifier are studied in depth,and the corresponding effective design methods are proposed.