Negative resistance oscillator/amplifier accumulator circuit

Abstract

A microwave oscillator/amplifier includes a plurality of TEM transmission lines each with a negative resistance device at one end and a lossy, matched termination at the other end. A resonant cavity is coupled to each TEM line so as to induce a parallel resonance on the lines at the region of coupling. Structural means are provided for maintaining the characteristic impedance of the TEM lines uniform along the length of said lines. Fabrication of a device in which the TEM line characteristic impedance was uniformly maintained along the line length at five times the optimum negative resistance of said negative resistance device is noted. Suggested levels of characteristic impedance are relatively low compared to prior art devices, none of which are known to attempt maintenance of characteristic impedance uniform along the length of the TEM transmission line. No impedance transformers are employed between the negative resistance device thus permitting the device to be located at the closest point to the resonant cavity at which the impedances presented by the cavity and the negative resistance device are equal in magnitude and opposite in sign. An efficient oscillator with practically no moding, spurious oscillations, or starting problems results.