Gain enhancement over a wideband in CPW-fed compact circular patch antenna

The present paper reports the gain enhancement over a wideband (12–15 GHz) in a coplanar waveguide (CPW)-fed circular patch antenna with circular defected ground structure (DGS). Two compact coplanar circular antennas have been designed and fabricated with and without DGS of same volume 18 × 20 × 1.6 mm3, built over FR4-epoxy substrate (εr = 4.4). Gain enhancement has been achieved by optimizing the current distribution with suitable DGS. For this purpose, structural designs have been optimized by parametric simulations in HFSS and CST MWS. Both the antennas can perform well in variety of wireless communication including WLAN IEEE 802.11 g/a (5.15–5.35 GHz and 5.725–5.825 GHz) and X-band applications including short range, tracking, missile guidance, and radar communication that ranges roughly from 8.29 to 11.4 GHz. The measured experimental results show that impedance bandwidth (S11 < −10 dB) of antenna with DGS is 100%. The antenna with DGS offers gain improvement by 2.7 dB for 13 GHz and 7 dB for 14 GHz. The performance of antenna with DGS is compared to conventional CPW-fed circular patch antenna (without DGS) in terms of reflection coefficient, radiation characteristics, and gain.