Constant-output-frequency, octave tuning range backward-wave parametric amplifier

This paper describes a varactor diode backward-wave parametric amplifier (BWPA) which operates in a new mode that yields a constant-output frequency as the amplification frequency is electronically turned over an octave signal tuning range. A theoretical discussion on the design considerations is presented and applied to the construction of an LF model (1.5-3.3 Mc). Experimental data on the important amplifier characteristics are given and shown to correlate well with theory. The amplifier yields stable gains in excess of 20 db over a greater-than-octave tuning range, and the output frequency (which is taken at the idler) has less than a ± 1.6 per cent variation over the octave band. The over-all effective receiver input-noise temperatures were measured and agreed well with theory, being about 160°K at the LF end of the band and increasing to 300°K at the HF end.