Ultrabroadband Electronically Tunable Oscillators

This paper describes the results obtained on two types of very broadband tunable sources. - A bipolar-varactor oscillator has been designed showing a tunability from 3 to 9,4 GHz. This result was obtained with a slope compensating circuit placed between the emitter and the hyperabrupt tuning varactor. The output power was 10 mW in the bandwidth. - A decade bandwidth FET-YIG tuned oscillator was calculated using two YIG spheres : one coupled to the gate and the other to the source. An experimental oscillator was realized with a linear tunability from 2 GHz to 20 GHz, without jumps, and few milliwatts output power.