Systems, such as receivers, are often designed as a block diagram that combines multiple component-level functions—e.g., a frequency mixer, a local oscillator (LO), and filters. When it is time to build the hardware system, such components are available from a large number of RF/microwave suppliers and in many different types of packages, allowing engineers to assemble a system design from practical components.

But when the need arises to squeeze a bit more system-level performance from a smaller package, many components suppliers can also provide standard and custom integrated microwave assemblies (IMAs). This makes it possible to construct a system from a smaller number of larger multifunction modules—one than often boasts size, weight, and performance advantages compared to what can be achieved by combining discrete RF/microwave components.

In many cases an IMA—or microwave integrated circuit (MIC), as it has been traditionally known—appears to resemble small systems (Fig. 1) housed within a rugged enclosure for protection and isolation. Many IMAs integrate different technologies as well as components, often blending DC circuitry with higher-frequency analog components and digital signal-processing functionality. As an example, Phase Matrix created a 9-to-15-GHz digitally tuned oscillator module by combining the outputs of multiple signal sources by means of Wilkinson power combiners (Fig. 2).

1. These compact modules are actually block frequency converters for satellite-communications (satcom) systems, helping to simplify either upconversion or downconversion. (Photo courtesy of MITEQ, Inc.)

2. This printed-circuit-board (PCB) multifunction module combines several oscillators and amplifiers to achieve high output levels across a wide frequency range with digital control built in. (Photo courtesy of Phase Matrix.)

GaAs MMIC amplifiers are used to maintain a required output level and tuning is by means of transistor-transistor-logic (TTL) control. The module also contains components not typically found in RF/microwave components, including electronically erasable programmable read-only memory (EEPROM) and a digital-to-analog converter DAC). The hermetic source adjusts by means of 12-b tuning and delivers 15-dBm output power with low noise across a temperature range of -40 to +85°C.