Inverted T-Shaped DGS loaded nearly square microstrip patch antenna for wireless applications

ABSTRACT This research presents an inverted ‘T’-shaped Defected Ground Structure (DGS)-loaded single feed circularly polarised nearly square microstrip patch antenna for wireless communication applications. The proposed antenna structure uses an inverted ‘T’-shaped DGS and exhibits an overall impedance (S11< −10 dB) of 665 MHz (12%) and an axial ratio bandwidth of 140 MHz (2.61%) with right-hand circular polarisation having a gain of 3.91 dBi. The proposed antenna is designed, simulated and fabricated using the FR4 substrate. The electrical size of the designed microstrip patch antenna is 0.238λ × 0.216λ. Using an inverted ‘T’-shaped DGS, the antenna size has been reduced by 13.8%. The detailed design and analysis of the proposed broadband circularly polarised microstrip patch antenna are discussed and presented. The fabricated antenna is tested, and the measured impedance bandwidth is 557 MHz (10%). The measured results are in good agreement with simulated results, and the proposed antenna can be suitable for WLAN, Wi-MAX and Hyper LAN applications.