Frequency Reconfigurability of SIW Microstrip Patch Antennas Using Various Nematic Liquid Crystals in the Ka Band

This work focuses on the use of three different types of liquid crystals, namely K15(5CB), E7, and GT3-23001, to achieve adjustable frequency ranges. These ranges are ∆fr = 1.89 GHz (from 29.907 GHz to 31.716 GHz), ∆fr= 3.236 GHz (from 28.48 GHz to 31.716 GHz), and ∆fr= 6.768 GHz (from 27.216 GHz to 33.984 GHz), respectively. Through simulations, it has been demonstrated that the anisotropy constant (∆εr=ε
r⫽
-ε
r⏊
|) of the liquid crystal has a significant impact on the range of frequencies that can be tuned, thereby expanding the possibilities for utilizing liquid crystals in the design of reconfigurable antennas operating at high frequencies. Liquid crystals offer several advantages such as low cost, compact size, and impressive performance, making them highly promising for the development of reconfigurable antennas suitable for 5G and IoT applications in Ka band.