The increasing need to improve the bandwidth and efficiency in antennas is a continuous topic of research in RF systems. However, when it comes to physical platforms that are electrically small relative to the desired frequency of operation, balancing miniaturization, bandwidth, and efficiency

is challenging and often counterintuitive. To overcome these challenges, we proposed utilizing a direct antenna modulated (DAM) electrically small antenna (ESA).

J. P. Dytioco Santos, F. Fereidoony, M. Hedayati and Y. E. Wang, "High Efficiency Bandwidth VHF Electrically Small Antennas Through Direct Antenna Modulation," in IEEE Transactions on Microwave Theory and Techniques, vol. 68, no. 12, pp. 5029-5041, Dec. 2020, doi: 10.1109/TMTT.2020.3016381.

We present a novel structure based on liquid crystal (LC) technology to achieve a high figure of merit (FOM) phase shifter that works at sub-6 GHz frequencies. The phase-shifting mechanism is enabled through the phase constant variation in the main microstrip line, which is loaded periodically by a variable equivalent capacitance controlled by a bias voltage.

M. A. Panahi, L. Yeung, M. Hedayati and Y. E. Wang, "Sub-6 GHz High FOM Liquid Crystal Phase Shifter for Phased Array Antenna," in IEEE Journal of Microwaves, vol. 2, no. 2, pp. 316-325, April 2022, doi: 10.1109/JMW.2022.3152208.