Utilization of artificial magnetic conductor for bandwidth enhancement of square patch antenna

In this paper, the enhancement of square patch antenna bandwidth using a structure of artificial magnetic conductor (AMC) is investigated numerically. The implemented AMC structure takes a planar structure which comprises of 4 identical square patches arranged in 2-2 array incorporated with resistors placed between two adjacent patches. The square patch antenna is designed to have resonant frequency of 2.4GHz. The total size of antenna including microstrip line feeding network is 38mm × 38mm. Here, the AMC structure and the antenna itself are deployed on an FR4 Epoxy dielectric substrate with relative permittivity of 4.2 and total thickness of 3.2mm. It is indicated that the proposed antenna is not only able to reduce patch antenna dimension by approximately 26% of the conventional antenna, but also able to improve the impedance matching. Minimum reflection coefficient (S₁₁) decreases up to -34.06dB, so that much wider bandwidth can be obtained. In other hand, the conventional antenna, i.e. square patch antenna without AMC structure has an undefined value of bandwidth due to its poor impedance matching. Hence, the proposed antenna provides a widened bandwidth that is up to 205MHz. Unfortunately, the gain of proposed antenna with AMC structure at resonant frequency falls up to -1.79dB which shows a trade-off between bandwidth and gain in the proposed modification.