Thick-film 3-stage m.i.c. IMPATT diode-amplifier on ferrite

A 3-stage hybrid m.i.c. gallium-arsenide IMPATT-diode amplifier is described with an output of 1.05 W at 9.2 GHz, a large-signal gain of 21 dB and a bandwidth to ¿3 dB greater than 1 GHz; the amplifier is stable at all input levels. The concept of an effective radius, first proposed to explain the properties of disc capacitors, has been used successfully in the circulator design. Close attention has been paid to screening the unencapsulated diodes to prevent r.f. radiation and to incorporating resistive-loading circuits to suppress spurious out-of-band oscillations.