Transferred electron oscillators for heterodyne receivers

Transferred electron oscillators (TEOs) are commonly used for local oscillator (LO) power in heterodyne receivers. These sources can be used to directly pump mixer circuits up to 160 GHz or to drive varactor frequency multipliers for applications that require a higher frequency LO. The advantages of TEOs over other sources include low noise operation, moderate power (10-50 mW) up to at least 160 GHz, broad band operation, relatively low cost, high reliability, and easy integration with the receiver system. The disadvantage of these oscillators is the mechanical tuning for the frequency and power backshorts. The TEOs described are all second-harmonic oscillators to insure reduced load pulling and lower noise than fundamental TEOs. Also, efficient power generation from fundamental current oscillations is difficult to achieve at frequencies above 100 GHz with short InP TEOs. The authors focus on the theoretical and experimental results for a continuously tunable 115-145 GHz (20-50 mW) low noise source, and some preliminary theoretical and experimental results at 160 GHz.