A 256-Element Dual-Beam Polarization-Agile SATCOM Ku-Band Phased-Array With 5-dB/K G/T

This article presents a $16\times 16$ dual-polarized $Ku$ -band (10.7–12.7 GHz) satellite communications (SATCOM) phased-array receiver with simultaneous dual-beam reception capability. The array incorporates 64 16-channel beamformer chips and 256 dual-polarized antennas. A dual-channel low noise amplifier (LNA) is employed on every antenna to lower the system noise figure (NF) and increase the antenna gain-to-noise temperature (G/T). The phased-array is built on a low-cost printed circuit board (PCB), with an antenna spacing of $\lambda $ /2 at 12.2 GHz in an equilateral triangular grid to result in ±70° scan volume, and is capable of receiving two concurrent data-streams with a distinct direction of arrival (DOA) since it employs two 64:1 Wilkinson combiner networks. A transmit band (14–14.5 GHz) filter is also implemented between the LNA and the beamformer chip. The 256-element array has a directivity of 28 dB at mid-band with a G/T of 5 dB/K ( $T_{\mathrm{ ant}}=20$ K), which results in a G/T of 11 dB/K for a 1024-element array. This array is a feasible solution for make-before-break connections and for multi-satellite reception systems, such as simultaneous television (TV) reception and connectivity.

I. Introduction

Satellite communications have relied on geosynchronous (GEO) satellites for many years. Covering a large area on the Earth’s surface, consumers have accessed them through parabolic dishes and mechanically steered antenna systems [1]–[9]. Although the demand for global internet connectivity has been soaring day by day, low-earth-orbit (LEO) and medium-earth-orbit (MEO) satellites could not take the place of the traditional systems due to the high user-terminal cost. Deploying thousands of rapidly moving satellites in the lower orbits requires inexpensive ground terminals which can electronically track the satellites without moving parts. With the deployment of 5G, the cost of phased-array antennas (PAAs) has dropped drastically, and low-cost silicon beamformer chips have enabled the commercial use of silicon beamformers in SATCOM and 5G systems [10]–[28]. Multi-satellite reception has also become a requirement for some LEO constellations for make-before-break systems.