A quasi-planar FET amplifier in integrated finline and microstrip technique

The design and performance of a single-stage 20-GHz GaAs FET amplifier in a quasi-planar technology are described. The component includes a compact, wideband transition between the finline input and output ports and the microstrip impedance-matching networks for the transistor. By virtue of a novel bias network which includes a microstrip bandstop filter and a 50- Omega resistor, this transition provides unconditional stability even at frequencies below cutoff of the finline ports. The overall amplifier has a gain of 6 dB at 20 GHz, and a 3-dB bandwidth of 17%.<
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