Chapter 13 - Monolithic Microwave Integrated Circuits

Abstract

Monolithic microwave integrated circuits (MMICs) and similar devices are used in a wide variety of receivers. These devices may be very wideband or relatively narrowband. Very wideband amplifiers have a bandpass (frequency response) of several hundred megahertz or more, typically ranging from sub-VLF to the low end of the microwave spectrum. One reason why very wideband amplifiers are rarer than narrowband amplifier circuits is that they were difficult to design and build until the advent of monolithic microwave integrated circuit devices. Several factors contribute to the difficulty of designing and building very wideband amplifiers. The MAR-X is a very simple device. The only connections are RF input, RF output, and two ground connections. The use of dual ground connections distributes the grounding, reducing overall inductance and thereby improving the ground connection. Direct current power is applied to the output terminal through an external network. The MAR-X devices can be connected in cascade, parallel, or push-pull. The cascade connection increases the overall gain of the amplifier, while the parallel and push-pull configurations increase the output power available. The MAR-X devices are an extremely easy way to build RF amplifiers from frequencies near DC to the low microwave region. They are easy to use and well behaved. Hobbyists will find them very convenient for a wide variety of applications.