A <i>Ka</i>-Band 64-Element Four-Beam Phased Array Receiver With Inter-Beam Interference Cancellation

Abstract

This article presents a Ka-band 64-element phased-array receiver with four simultaneously reconfigurable beams for millimeter-wave (mmW) satellite communications, where each beam utilizes the maximum available antenna aperture to enhance the combining gain. To address the design challenge of the large area induced by the multiple beamforming networks (BFNs), the beamformer utilizes a digital-assisted variable-gain phase-shifting technique and an active combining scheme to enable compact implementation and facilitate array design. This article also proposes a cancellation-based inter-beam interference reduction technique using multiple beams to support steerable nulling to boost beam-to-beam isolation, which offers an alternative solution to reduce array sidelobes. The proposed <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$8\times 4$ </tex-math></inline-formula> beamformer integrates 32-path independent plural weighting channels and is fabricated in 65-nm CMOS with a compact chip area of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$5.3\times 4$ </tex-math></inline-formula> mm2. Each element achieves a gain of 26.7 dB, a noise figure (NF) of 3.7–4.5 dB, and an input-referred 1-dB gain compression point (IP1dB) of −32.5 dBm at 29.5 GHz. The proposed 64-element receive phased array is capable of scanning ±50° at 29.5 GHz without grating lobes at both the azimuth and elevation directions. To the authors’ best knowledge, the proposed phased-array receiver presents the largest number of co-aperture reconfigurable beams among mmW-integrated RF-beamforming phased arrays.