Low-Noise Tunnel-Diode down Converter Having Conversion Gain

This paper describes the use of the new tunnel diode in a down converter. An experimental UHF circuit converting from a signal frequency of 210 mc to an intermediate frequency of 30 mc is used to illustrate the feasibility of this new converter. Conversion power gain of 22 db with less than 3 db noise has been achieved with gallium arsenide diodes. The circuit analysis proceeds from the basic nonlinear resistance of the tunnel diode I-V characteristic. Equations are developed for conversion gain, bandwidth and noise figure. From these equations, criteria are derived for the choice of diode characteristics and circuit parameters to obtain optimum performance.