An FET oscillator element for spatially injection locked arrays

A new type of oscillator element for spatially injection locked arrays is presented. The element consists of an FET oscillator equipped with two patch antennas: one for reception for the injection signal and the other for radiating the oscillator output power. This element exhibits much broader locking bandwidths for a given injection signal than previous approaches. Prototype circuits operating at 6 GHz exhibit a 270-MHz locking range with 46.5-dB isotropic gain. The elements operate independently, so that the array is synchronized only when the injection signal is present. Using this approach, broad locking bandwidths are achieved with relatively low injected signal levels. In addition, using the elements described, arrays can be constructed which focus the radiated field.<>