Overview

From APPLIED MICROWAVE & WIRELESS, VOL. 1, NO. 3, NOVEMBER/DECEMBER 1989

Since their revival in popularity [1] due to the MMIC revolution, distributed amplifiers have been targeted for a wide range of applications. Their ease of design, good input and output return losses, flat gain over large bandwidths, and relative insensitivity to processing variations have been given as reasons for their popularity [2].

The large-signal performance of distributed amplifiers has not been as favorable. This is not an inherent property of distributed amplifiers, but rather a consequence of conventional small-signal design criteria.

The output power of 4 to 18 GHz conventionally designed distributed amplifiers at 1 to 2 dB of gain compression, for example, typically decreases by 4 6 dB at the high end of the band relative to the level at the low end. As a result, to meet system requirements, a large amount of gate periphery is required to give the minimum power, which is required at the high end of the band. The power available at the low end of the band by this scenario is, therefore, much more than necessary, which implies that the circuit also consumes much more dc power than necessary.

This paper presents an alternate design method that yields more uniform power performance characteristics from distributed amplifiers, discusses examples of performance improvements expected from using this design technique...