Time-Modulated Antenna Array for Real-Time Adaptation in Wideband Wireless Systems—Part I: Design and Characterization

This paper presents a design of a time-modulated antenna array (TMAA) with substantially wider bandwidth and higher efficiency than have already been presented in the literature. The TMAA is designed for 5.4-5.8 GHz frequency band. More than 50 MHz of channel bandwidth is achieved by utilization of ultrafast microwave switches, digital delay lines with 60 ps step, and fast control circuitry. The efficiency is improved by alternate switching between the array elements instead of switching between the array element and a matched load. Moreover, a mathematical derivation of optimal switching sequence is given. The beam steering at the first sideband frequency was obtained with a 1° step in a range from -50° to 50°. The TMAA has been evaluated by means of the radiation pattern measurements at different sideband frequencies.