A monolithic microwave integrated circuit (MMIC) is a microwave circuit in which the active and passive components are fabricated on the same semiconductor substrate. The frequency of operation can range from 1 GHz to well over 100 GHz, and a number of different technologies and circuit approaches can be used. The additional term 'monolithic' is necessary to distinguish them from the established microwave integrated circuit (MIC), which is a hybrid comprising a number of discrete active devices and passive components integrated onto a common substrate using solder or conductive epoxy adhesive. These became known as integrated circuits because the alternative is to employ hollow metal waveguides, where the inclusion of active devices is a matter requiring considerable mechanical design and workshop machining. The purpose of this chapter is to provide a general background in the history, applications and technology of MMICs. The advantages and disadvantages of MMICs compared with hybrid microwave integrated circuits are discussed in detail. The large range of available device technologies is introduced, and the major applications that have driven the development of MMIC technology are described.

It is the extensive use of passive components that makes MMIC design so different to conventional integrated circuit design and layout. In MMIC design, passive components are used for impedance matching, DC biasing, phase-shifting, filtering and many other functions. The authors describe the key passive components that are used in MMIC design. These components include not only the basic lumped inductors, capacitors and resistors, but also a wide range of distributed transmission-line components. These transmission-line components include microstrip lines and elements such as bends and T-junctions, as well as standard building blocks like couplers and power splitters/combiners. Most often, these building blocks are realised in the microstrip transmission-line medium. However, other types of transmission line such as coplanar waveguide (CPW), slotline, and 'thin-film microstrip' are being used more and more.

The authors describe the most important techniques used for MMIC amplifier design. The classical theory and analysis of S-parameters, two-port stability and unilateral transducer gain are briefly reviewed. The key impedance matching techniques and DC biasing circuits are described before introducing the five major MMIC amplifier topologies: the reactively matched amplifier, the lossy match amplifier, the feedback amplifier, the distributed amplifier and various forms of actively matched amplifier. Finally, the design of low noise and high power amplifiers is considered.

Mixers are key elements in nearly all RF and microwave communication receivers, transmitters and signal generators. They have the prime function of converting signals from one frequency to another, where other circuit functions like amplification, filtering, detection and transmission can be performed more effectively. In this work the authors cover the following topics: analysis of mixer circuits; diode mixers; coupling structures; active FET mixers; resistive FET mixers; image-rejection mixers; single-sideband mixers; sub-harmonically pumped mixers; and distributed FET mixers.

A phase shifter is a control device found in many microwave communication, radar and measurement systems. In this work the author describes many of the design techniques for MMIC phase shifters, implemented under either analogue or digital control.

RFICs and MMICs are finding more and more applications in the commercial sector, but fierce competition between manufacturers and between different technologies has led to immense pressure on manufacturing costs: single-chip solutions with minimum chip size are demanded. Now there is immense demand for the 'single chip radio', and a transceiver design must increasingly integrate RF, mixed signal and digital functions. In this work the authors give an insight into some of the more advanced techniques for the design of integrated transmitters and receivers. In many cases, new architectures have been developed as a means of replacing expensive components, and this is especially true of filters.