Sidelobe Reduction by Subarray Stacking for Uniformly Excited mmW Phased Arrays

The performance of multi-user millimeter-wave (mmW) systems is limited by relatively high sidelobe levels (SLLs) of antenna arrays. Per-antenna amplitude control can be used to adjust the amplitudes to reduce the SLL, but the reduction is often achieved at the cost of reduced transmitted power. Large two-dimensional (2D) antenna panels used in mmW phased arrays, however, allow the 2D antenna configuration to be reconfigured to reduce the SLL. In this paper, we present a simplified approach for sidelobe reduction by stacking multiple uniform linear arrays of different size to reduce the sidelobes across the horizontal plane. The approach is based on the relation between the number of antenna elements and the directions of null and sidelobe maxima. The sidelobe reduction is demonstrated by both simulations and measurements. The measurements are carried out in an anechoic chamber at 28 GHz center frequency using a 100 MHz wide modulated 5GNR waveform.