Toward 5G/mm-Wave Shape-Changing Origami-Inspired Phased Arrays for Near-Limitless Arbitrarily Reconfigurable Radiation Patterns: Realization, Actuation, and Calibration

Abstract

This article presents the first shape-changing phased array operating at 28 GHz as an alternative to traditional planar phased arrays. By combining electrical beamsteering with mechanical shape change, this design achieves high degrees of freedom, resulting in near-limitless radiation pattern reconfigurability and overcoming the tradeoff between gain and angular coverage. Utilizing the eggbox origami structure, a 4-D multifaceted foldable phased array is developed, and a modular tile-based (unit-cell) approach is employed to enable TX/RX selective activation and scalability to massive MIMO. This results in near 360° continuous beam steering in the azimuth plane with reconfigurable multibeam or quasi-isotropic radiation patterns. Additive manufacturing processes are employed to realize the first shape-changing phased array at a miniaturized millimeter scale. The eggbox phased array features highly integrated on-structure beamformer ICs and a flexible feeding network utilizing a uniquely designed foldable interconnect. As the first additively manufactured mm-wave hinge interconnects, the presented “arch” interconnect exhibits near-constant insertion loss of 0.02 dB/mm across various folding angles and cycles. In addition, a microservo-based actuation mechanism is designed to precisely control the origami folding action. Measurements demonstrate the phased array’s pattern reconfigurability, and its effectiveness is further validated in an orthogonal frequency division multiplexing (OFDM)-based communication testbed setup. Furthermore, this article provides a holistic multidisciplinary framework guiding the development of a new era of mm-wave shape-changing phased arrays, encompassing considerations in hardware realization, actuation, and 3-D beam shaping/calibration. Given its multitude of novel features, the eggbox phased array can enable a plethora of applications, ranging from multimode in-band full-duplex applications to multifunction multibeam use cases, extreme interference mitigation, and space-constrained deployments.