A Monolithically Integrable Reconfigurable Antenna Based on Large-Area Electronics

Abstract

Reconfigurable antennas introduce unique and dynamic system capabilities for wireless communication and sensing, by enabling controllable radiation pattern, frequency response, and polarization of electromagnetic (EM) waves. The antenna’s physical dimensions are critical to enhancing control of radiative characteristics, making it necessary to distribute RF control devices across a large-area aperture. Previous reconfigurable antennas have been limited in scale and per- formance by the need to assemble discrete active components. Large-area electronics (LAE) is a technology that can enable monolithic reconfigurable antennas, with flexible and large form factors. However, conventionally the speed of LAE, specifically of thin-film transistors (TFTs), has been restricted to 10–100 MHz. In this work, a reconfigurable antenna based on LAE RF TFTs is achieved through a combination of: 1) materials and device enhancements pushing fundamental TFT performance metrics to the giga-Hertz regime and 2) an architecture that employs the TFTs as passive switches, rather than active amplifiers, to enable aggressive biasing for high-frequency operation, yet within the breakdown limits. A 9 × 9 cm2 reconfigurable antenna consisting of an 11 × 11 array of metal patches as sub-radiators controlled by 208 TFT-based RF switches is demonstrated. Far-field and S-parameter measurements show reconfigured beam steering by 90◦ and resonant-frequency tuning by 200 MHz.