Antenna Preprocessing and Element-Pattern Shaping for Multi-Band mmWave Arrays: Multi-Port Receivers and Antennas

The ability to pre-process incident RF signals on a single-antenna aperture in a multi-port antenna/receiver architecture with reconfigurable element patterns can allow unique functionalities, that are distinct from traditional transceivers with single-port antennas. The multiple ports allow reconfigurable passive spatial signal processing before the transceiver through element-pattern synthesis including element maxima and notch control. In this article, we show that when combined in an MIMO array, tailoring of element patterns through such multi-port receiver-antenna architectures can allow periodic arrays to operate over a wide frequency range, even at element spacings approaching one wavelength long. Such a frequency-reconfigurable operation of scalable arrays is important for future multi-band 5G systems and beyond. When operated at high frequencies in the spatially undersampled regime, array grating lobes can be suppressed by orienting the element-pattern notches toward the grating maxima in a reconfigurable fashion. In addition, the multi-port electromagnetic (EM)–circuit interface can allow spatial signal processing before the transceivers including the passive suppression of a spatial interferer at the antenna interface. Through a codesign methodology between the EM interface and the multi-port receiver architecture, we present an architecture with a bandwidth across 37–73 GHz for broadside incidence, reconfigurable element patterns that allow antenna-level signal processing, spatial, frequency, and partial polarization diversity.