Series-parallel operation of Gunn diodes - A new approach to high power solid-state microwave sources

The series operation of Gunn diodes with above critical noL products has been considered to be impractical. It was found that one of the diodes in the series connected chain tends to capture most of the bias voltage leaving the rest of the diodes with sub-threshold bias. The diode which captures the voltage, being over biased, generates noise instead of coherent oscillations. The sub-threshold biasod diodes act as resistive loads.