Transmission Type Negative Resistance Amplifiers

Reflection amp1ifiers using negative resistance diodes such as IMPATI diodes have been developed extensively [1] and commercial amp1ifiers of this type are available. These circuits require a circulator with each diode together with the tuning and matching circuitry. Circulators add to the complexity and cost of the circuit and since each circulator has a finite bandwidth and a non-zero insertion loss, their inclusion inevitably degrades the circuit performance. In this paper we present a different approach which employs a transmission type circuit that does not require circulators. Three types of transmission amplifiers are theoretically possible and the final configuration depends on the design procedure. We shall call the three types: The filter amplifier; The filter amplifier with gyrators; and the matched-section amplifier.