43 Solid state circuits 43. 1 Introduction 43.2 Amplifiers 43.3 Oscillators 43.4 Multipliers I. J. Bahl ITT Gallium arsenide 13.6 Control Circuits Technology Center 43.7 Summary and Future Trends 43. 1 Introduction Over the past two decades, microwave active circuits have evolved from individual solid state transistors and passive elements housed in conventional waveguides and/or coaxial lines to fully integrated planar assemblies, including active and passive components and interconnections, generically referred to as a microwave integrated circuit(MIC). The hybrid microwave integrated circuit(HMIC) consists of an interconnect pattern and distributed circuit components printed on a suitable substrate, with active and lumped circuit components(in packaged or chip form) attached individually to the printed interconnect circuit by the use of soldering and wire bonding techniques. The solid state active elements are either silicon or gallium arsenide(or other Ill-V compound)devices. More recently, the solid state monolithic microwave integrated circuit(MMIC)approach has become commonplace. In MMICs, all interconnections and components, both active and passive,are fabricated simultaneously on a semi-insulating semiconductor substrate(usually gallium arsenide, GaAs)using deposition and etching processes, thereby eliminating discrete components and wire bond interconnects. The term MMIC is used for circuits operating in the millimeter wave(30-300 GHz)region of the frequency spectrum well as the microwave(1-30 GHz) region. Major advantages of MMICs include low cost, small size, low weight, circuit design flexibility, broadband performance, elimination of circuit tweaking, high-volume man ufacturing capability, package simplification, improved reproducibility, improved reliability, and multifunction performance on a single chip Microwave circuits use two types of active devices: two-terminal devices, referred to as diodes, such Schottky, Gunn, tunnel, impact avalanche and transit time(IMPATt), varactor, and PIN, and three-terminal devices, referred to as transistors, such as bipolar junction transistor(B]T), metal semiconductor field effect transistor(MESFET), high electron mobility transistor(HEMT), heterostructure FET (HFET), and heterojunc tion bipolar transistor(HBT). Microwave circuits using these devices include amplifiers, oscillators, multipli ers,mixers, switches, phase shifters, attenuators, modulators, and many others used for receiver or transmitter applications covering microwave and millimeter wave frequency bands. New devices, microwave computer aided design( CAD) tools, and automated testing have played a significant role in the advancement of these circuits during the past decade. The theory and performance of most of these circuits have been well documented Kollberg, 1984; Bhartia and Bahl, 1984; Pucel, 1985; Maas, 1986; Bahl and Bhartia, 1988; Goyal, 1989; Ali et al., 1989; Chang, 1990; Vendelin et al., 1990; Ali and Gupta, 1991; Chang, 1994]. Solid state circuits are extensively used in such applications as radar, communication, navigation, electronic warfare(EW), smart weapons, c 2000 by CRC Press LLC© 2000 by CRC Press LLC 43 Solid State Circuits 43.1 Introduction 43.2 Amplifiers 43.3 Oscillators 43.4 Multipliers 43.5 Mixers 43.6 Control Circuits 43.7 Summary and Future Trends 43.1 Introduction Over the past two decades, microwave active circuits have evolved from individual solid state transistors and passive elements housed in conventional waveguides and/or coaxial lines to fully integrated planar assemblies, including active and passive components and interconnections, generically referred to as a microwave integrated circuit (MIC). The hybrid microwave integrated circuit (HMIC) consists of an interconnect pattern and distributed circuit components printed on a suitable substrate, with active and lumped circuit components (in packaged or chip form) attached individually to the printed interconnect circuit by the use of soldering and wire bonding techniques. The solid state active elements are either silicon or gallium arsenide (or other III–V compound) devices. More recently, the solid state monolithic microwave integrated circuit (MMIC) approach has become commonplace. In MMICs, all interconnections and components, both active and passive, are fabricated simultaneously on a semi-insulating semiconductor substrate (usually gallium arsenide, GaAs) using deposition and etching processes, thereby eliminating discrete components and wire bond interconnects. The term MMIC is used for circuits operating in the millimeter wave (30–300 GHz) region of the frequency spectrum as well as the microwave (1–30 GHz) region. Major advantages of MMICs include low cost, small size, low weight, circuit design flexibility, broadband performance, elimination of circuit tweaking, high-volume man￾ufacturing capability, package simplification, improved reproducibility, improved reliability, and multifunction performance on a single chip. Microwave circuits use two types of active devices: two-terminal devices, referred to as diodes, such as Schottky, Gunn, tunnel, impact avalanche and transit time (IMPATT), varactor, and PIN, and three-terminal devices, referred to as transistors, such as bipolar junction transistor (BJT), metal semiconductor field effect transistor (MESFET), high electron mobility transistor (HEMT), heterostructure FET (HFET), and heterojunc￾tion bipolar transistor (HBT). Microwave circuits using these devices include amplifiers, oscillators, multipli￾ers, mixers, switches, phase shifters, attenuators, modulators, and many others used for receiver or transmitter applications covering microwave and millimeter wave frequency bands. New devices, microwave computer￾aided design (CAD) tools, and automated testing have played a significant role in the advancement of these circuits during the past decade. The theory and performance of most of these circuits have been well documented [Kollberg, 1984; Bhartia and Bahl, 1984; Pucel, 1985; Maas, 1986; Bahl and Bhartia, 1988; Goyal, 1989; Ali et al., 1989; Chang, 1990; Vendelin et al., 1990; Ali and Gupta, 1991; Chang, 1994]. Solid state circuits are extensively used in such applications as radar, communication, navigation, electronic warfare (EW), smart weapons, I. J. Bahl ITT Gallium Arsenide Technology Center