Four-watt 20-GHz partial monolithic amplifier

A 4-W power amplifier with 28% power-added efficiency at 20 GHz has been demonstrated using 0.25- mu m heterostructure FET (HFET) device technology. This two-stage amplifier features a mostly monolithic approach with a portion of the input and output matching networks on alumina. The output matching network employs reactive matching elements on GaAs, followed by a Chebyshev coupled-line transformer/combiner on alumina to achieve a low-impedance match with minimal loss. Discrete 0.25- mu m HFET device results at 18 GHz and 20 GHz as well as amplifier design and performance over a >3 GHz band are presented.<
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