Angle accuracy improvement using DMC randomization for phased array

It is shown that, as an alternative to using cable randomization, decorrelation can be obtained by randomizing the element phase settings at one half of the LSB value. As demonstrated in computer simulations for both methods, this randomization is not only more accurate than cable randomization; it can also be obtained cost-free in most modern phased arrays. To decorrelate the quantization error using DMC (distributed modular controller) randomization, a random number stored in a DMC register is added to DMC's phase shift calculation. The maximum value of this random number is one-half of the phase shifter LSB. The lower bound for the LSB of this random number is equal to the LSB of the DMC. Therefore, the number of bits in this random number is equal to or less than the difference between the DMC word length and the number of bits in the phase shifter. The choice of randomization bit length is affected by tradeoffs involving DMC cost and throughput and array pointing accuracy. Some of these tradeoffs are summarized for a 16-b DMC.<>