Transmission-type injection locking of GaAs Schottky-barrier FET oscillators

Transmission-type injection-locked oscillators equipped with both signal-input and power-output ports are examined and compared with traditional reflection-type injection-locked oscillators. It is shown that the locking range of transmission types always differs from that of reflection types by a factor of G sub s/G sub p, where G sub s is the maximum stable gain of the two-port oscillator and G sub p is the square root of the output power ratio of the two ports. Experiments on common-source injection-locked oscillators using GaAs FET chips are described and demonstrate that, with transmission types, a 1.8 times wider locking range can be obtained than with reflection types.