Thinned Randomized 27–29 GHz TX and RX Arrays With Low Sidelobe Levels for Radars and 5G Communications

This article presents a novel approach for radars with a greatly reduced number of elements while still keeping narrow beamwidths and low sidelobe levels. The design is based on thinned transmit (TX) and receive (RX) arrays, each one randomized in an orthogonal fashion, such that the high sidelobes in one pattern (TX or RX) are greatly reduced by nulls in the other pattern (RX or TX). The goal is to build communication arrays and radars with narrow beamwidths but with one-half or one-quarter of the elements in the TX and RX arrays. This approach lowers the cost of large-aperture systems typically requiring hundreds or thousands of elements, while still keeping a high degree of fidelity in the patterns (beamwidth, sidelobes, and scan volume). The thinned-array impact on the TX effective isotropic radiated power (EIRP), RX gain, and 16- and 64-QAM error vector magnitude (EVM) versus radiated power are also considered in this article. These concepts can be applied to 24- and 77-GHz automotive radars for collision avoidance and imaging systems, and in $X$ -, $Ku$ -, and $Ka$ -band air-to-air due-regard radars, landing systems, and other applications.