Microwave time delay beamforming using optics

A practicable method of driving 2-D arrays using time delay waveforms for both transmit and receive is presented. An optical subsystem generates a set of delayed signals which are transferred to the elements by fiber optics. The time delays are generated by creating frequency-dependent microwave phase shifts in the optical system. An optical fiber array spatially samples optical wavefronts and transfers the optical signals to the array where they are heterodyne detected to recreate the microwave signals at the input to transmit-receive (TR) modules. This process essentially extends the backplane of the antenna back to the control system where element level operations may be performed. All beamforming and nullforming functions may be implemented, e.g. monopulse. The requisite TR modules have no phase shifters and a minimum of logic