A KA band MMIC oscillator incorporating a novel injection locking circuit

A GaAs MMIC oscillator operating around 34 GHz has been designed and tested. This circuit incorporates a novel type of on-chip injection locking configuration, removing the requirement for off-chip couplers/circulators which would normally be required for typical reflection type injection locking applications. This configuration provides a separate injection locking port on the MMIC by utilising the (normally unwanted) parasitic inductance of a via-hole at the gate resonator circuit of the oscillator. The circuit has been shown by measurement to be capable of fundamental and subharmonic harmonic locking. The circuit was also employed in a novel fashion to produce a direct phase shift keyed modulator. In this configuration the circuit was found to produce up to 157° of phase shift. Applications of this circuit include a stabilised local oscillator or a direct phase shift keyed modulator