Liquid crystal-based reconfigurable antenna for 5G millimeter-wave

Abstract

This paper proposed a frequency reconfigurable antenna that utilizes a multilayer structure of liquid crystal (LC) material. This antenna design incorporates a three-layer stacked structure to create an LC-injected cavity. The inverted microstrip line structure is designed to be in contact with the LC, serving as both a radiating element and a bias electrode. A parasitic patch is placed at the top of the antenna to enhance bandwidth. To prevent interference with DC and RF sources, a bias tee is integrated into the microstrip line input. Experimental results demonstrate that the proposed antenna exhibits excellent impedance matching and stable radiation patterns within the operational frequency range. By comparing the simulated performance of the existing LC antenna with our proposed design, the bandwidth is tripled at a center frequency of 30.3 GHz. In addition, the effective area of the proposed reconfigurable antenna (154 mm 2 ) is 24.6% of the area of the previous reconfigurable antenna (625 mm 2 ).Frequency reconfigurable antennas are widely utilized in modern wireless communication systems due to their ability to dynamically alter frequency characteristics and good electromagnetic compatibility. To satisfy the requirements of miniaturization, broadband, and functional diversification of wireless communication system development, frequency reconfigurable antenna is becoming more and more popular. A large number of frequency reconfigurable antenna have been reported [1][2][3][4][5] , and their reconstruction methods are various. The traditional methods of using PIN diodes and MEMS switches to achieve antenna frequency reconstruction are limited by the inherent size of the switch and the operating frequency band [6][7][8][9] . Because the theoretical design of the variable capacitance of the varactor diode is not quite consistent with the actual, and the experimental design is difficult, the application of the varactor diode in the frequency reconfigurable antenna is relatively limited. The use of LC materials to achieve frequency reconfigurability in the millimeter-wave band is more advantageous than the above methods. Despite the many advantages of LC, many studies based on LCs do not provide measurement results 10,11 . The above studies do not discuss the design of an antenna structure that can be applied to 5G millimeter wave 12,13 .To solve some issues discussed above, in this paper a reconfigurable antenna with parasitic elements, electromagnetic band gap structure and LC is presented. The antenna can achieve wide bandwidth and continuous tunable in 5G millimeter wave band. The paper is organized as follows. Some introductions about the research of reconfigurable antenna are introduced in "Introduction" section. "Operating principle and antenna design" section introduces and analyzes the electromagnetic properties and structure of the reconfigurable antenna. The optimized antenna parameters and corresponding measured outcomes are presented in "Experimental results and discussion" section. Finally, "Conclu...