A phase-locked-loop approach has been adopted in order to realize a Ku-band transferred electron source with good power, stability and operational bandwidth. By arranging to interface with a u.h.f. reference, namely one of the new generation surface acoustic wave oscillators, the multiplier is simplified and the whole of the microwave circuit can be configured on a single compact m.i.c. The problem of maximizing the output of the transferred electron oscillator source in the rigid stripline medium has been solved by providing manual tuning elements together with an edge mounted device. Details of the circuit design and operation of the module are given.