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A step attenuator finds wide-spread usage as a means of accurately extending the attenuation range of test and measurement instruments. A typical application would be to extend the output amplitude range of a microwave signal generator. Often an amplitude control loop can accurately set the power or gain level over three or four decades of range, but frequently this is not enough range. Historically, the mechanical step attenuator has been the preferred solution.

Harmonic balance (HB) analysis is a method used to calculate the nonlinear, steady-state frequency response of electrical circuits. It is extremely well-suited for designs in which transient simulation methods prove acceptable, such as dispersive transmission lines in which circuit time constants are large compared to the period of the simulation frequency, as well as for circuits that have a large number of reactive components. In particular, harmonic balance analysis works extremely well for microwave circuits that are excited with sinusoidal signals, such as mixers and power amplifiers.

The debate over GaAs versus CMOS has been reinvigorated by recent industry events. This includes the sale of CMOS cellular power amplifier (PA) house Axiom Microdevices to GaAs cellular PA manufacturer Skyworks as well as the emergence from “stealth mode” of CMOS cellular PA startups Black Sand Technologies and Javelin Semiconductor. In terms of market share, since TRW Semiconductor paired with RF Micro Devices in the mid-­‐ to-­‐late 1990s, the GaAs heterojunction bipolar transistor (HBT) has been the standard bearer for mobile phone PA performance, cost, and manufacturability. GaAs houses that design, manufacture and package their own PAs and other RF components dominate today’s cellular power amplifier market.