In a quasi-optical oscillator array the output of a large number of oscillators are combined coherently with good efficiency to produce high powers at millimeter-ware frequencies. By placing the array in a fabry-perot resonator, high quality factors can be achieved. To further improve the stability of the output signal, an external locking signal can be used. The locking signal prevents the array's operating frequency from drifting and jumping modes, and also reduces the phase noise. The injection locked signal can also be used to fm modulate the array's output. We propose to investigate schemes for fundamental and sub-harmonic injection locking of quasi-optical arrays. Two distinct quasi-optical schemes for efficient coupling of the signal into the array will be explored. An alternative scheme in which the locking signal is fed directly onto the wafer using an integrated diode multiplier will also be examined. Preliminary tests of this scheme will be performed with a 10 GHz array that has already been built. The key figure of merit is the bandwidth over which injection locking is obtained for a given power. In parallel with this effort, a modelling program to study oscillator interactions will be created.Anticipated
Benefits:Recent demonstrations of quasi-optical power combining have generated interest in the applicability of these arrays to communication and radar systems. These arrays are small and light-weight and can be fabricated monolithically at relatively low cost.
