4. Microwave integrated circuits

4.1 Introduction

A monolithic microwave integrated circuit (MMIC) consists of the integration, on the same semiconductor substrate (Si, GaAs, InP, GaN), of active and passive elements performing a complete function (amplifier, mixer, oscillator, etc.). The MMIC concept is an old one, and these circuits have been on the market since the mid-1980s. Compared with hybrid circuits, where the various chips (transistors, etc.) are mounted on a printed circuit board, monolithic circuits offer the following advantages:

• The absence of wire connections means fewer parasitic elements and greater reliability, since connections are the source of most operating faults;

• circuit size reduction ;

• ...