Varactor-based Frequency-reconfigurable Dual-polarized mm-Wave Antenna Array for Mobile Devices

In this paper, a dual-polarized frequency-reconfigurable mm-wave patch antenna array is described. The design incorporates varactor diodes symmetrically loaded onto the four corners of square patch. Parallel plate series capacitors are constructed to achieve required low total capacitance by moving an inner layer. Additionally, novel dual-function shorting vias implemented into structure, which serve as RF choke for providing dc-bias voltage varactors, and behave shunt inductive loadings improve radiation efficiency. A four-element implemented, placed 21×4.5mm 2 cavity. proposed can be tuned from 23.2 30.2 GHz adjusting 0.22 0.033 pF. achieves over 20-dB isolation between orthogonal-polarized elements, more than 15-dB same-polarized elements. Total efficiency exceeds -2.5 dB across tuning range. Peak gain varies 8.9 10.5 dBi. offers notable advantages including wide frequency-tuning range, high efficiency, compact size, beam-forming capability.