Antenna Array Gain and Capacity Improvements of Ultra-Wideband Millimeter Wave Systems Using a Novel Analog Architecture Design

In this letter, we address the issue of beam-squinting encountered in ultra-wideband millimeter wave mobile communication systems. First, the beam-squinting effects on the antenna array gain and the usable bandwidth of these systems are analyzed. The obtained results show that, in ultra-wideband communication systems, beam-squinting causes loss in array gain and limits the achievable capacity. To mitigate these effects, a new analog architecture design, that improves the array gain and the achievable capacity, is proposed. The proposed architecture is most suitable for delay-sensitive or computational power constrained applications and does not require the computation of any compensation matrix in the digital domain. In addition, the exact expression for the array gain of the proposed analog architecture is derived. To further simplify the evaluation of the system performance, an approximated closed-form expression for the array gain is derived. Furthermore, to evaluate the performance of the proposed design, rigorous numerical results concerning different system parameters are provided in this letter.