The Effects of Imbalanced Phase Shifters Loss on Phased Array Gain

In the presence of imbalanced insertion loss of phase-shifters, satisfying phase conjugate condition does not necessarily lead to the maximum phased array gain. This paper introduces noncoherent beamforming and uses lab-measured characteristics of varactor-based phase shifters to prove that by perturbing coherency partially, the array gain can increase significantly, e.g., 1.6 dB for a 12 element array. Moreover, it is shown that reduction in the average insertion loss increases the array efficiency by almost the same amount. These results are extendible to the optical beamforming networks where different lengths of fiber are used to make true time delay lines.