Performance enhancement of planar dipole antennas using frequency selective surface technique combined with mushroom-like electromagnetic band gap

The development of a high-performance antenna for digital television receivers was carried out by integrating a frequency selective surface (FSS) technique with electromagnetic bandgap (EBG) metamaterial structures in the form of mushroom-type cavities. The base antenna used in this study is a planar dipole, which inherently exhibits narrow bandwidth and low gain, rendering it insufficient for digital television signal reception. To address this limitation, a band-notched technique was first applied by etching slots into the antenna structure to broaden its impedance bandwidth across the required frequency range. However, the resulting antenna still exhibited low gain performance. To improve gain, a mushroom-type EBG structure was designed and implemented as a reflector positioned behind the antenna. This configuration resulted in an average gain enhancement of approximately 3 dBi. However, we observed a decrease in the bandwidth, which was insufficient to cover the required frequency range for digital TV reception. To overcome this issue, a frequency selective surface (FSS) structure was introduced and designed to resonate at the desired frequency range, aiming to enhance the bandwidth. When the FSS was put in front of the antenna, the range of frequencies it could effectively use grew a lot, completely covering the needed frequency range while still benefiting from the gain boost from the EBG reflector. As a result, the proposed antenna achieved a gain ranging from 7.2 to 8.03 dBi and an impedance bandwidth spanning 462–951 MHz.