A novel analysis of the beam squinting in wideband phased array digital I/Q transmitters

This paper investigates the beam squint of direct conversion phased array transmitters with quadrature modulation and digital beam-forming. Beam squint occurs due to frequency dependent beam forming and leads to signal deterioration. It is analyzed in terms of EVM and maximum bit-rate, using both analytical and numerical computation. Various results illustrate the dependencies of the error mechanism on key design parameters in mm-wave transmitters. It is shown that having 14 elements and 120° scanning angle limits the theoretical maximum bitrate by 84% We show that using partial symbol delay in baseband, the EVM can be improved up to -30dB for 10 elements and more, without any apparent disadvantages. Moreover the bitrate theoretical maximum is increased by 4 times.