Enhancing Microstrip Patch Antenna Performance at 14 GHz Using Hexagonal-Shaped Artificial Magnetic Conductors

This paper presents the design and numerical simulation of a compact 14 GHz rectangular microstrip patch antenna integrated with a hexagonal-shaped artificial magnetic conductor (AMC) for enhanced radiation performance. The proposed antenna configuration consists of a conventional rectangular microstrip patch positioned above a compact hexagonal AMC structure implemented on an FR-4 substrate. The AMC unit cell features a hexagonal patch with an edge length of 6.41 mm and an overall substrate size of 24 mm × 24 mm, corresponding to subwavelength dimensions at the operating frequency. Full-wave simulations conducted with CST Studio Suite demonstrate that incorporating the AMC results in significant performance improvements without increasing the antenna's physical size. Specifically, the antenna gain is enhanced from 5.65 dBi to 6.95 dBi (approximately 23% improvement), while the directivity increases from 7.21 dBi to 8.56 dBi (approximately 19% improvement) compared to the conventional antenna without AMC. The AMC exhibits an operational bandwidth of approximately 280–300 MHz around the center frequency, based on the ±90° reflection-phase criterion. Moreover, the proposed antenna demonstrates excellent impedance matching with a minimum return loss (S11) of −38 dB at 14 GHz, confirming stable operation at the target frequency. These quantitative results clearly demonstrate the effectiveness and potential of hexagonal AMC-backed antennas as a viable and compact solution for high-performance microwave communication applications.