A compact monopole antenna for ultra-wideband applications

Abstract

In this paper, a slotted circular ultra-wideband (UWB) microstrip patch antenna is reported. The antenna is designed, simulated, fabricated, and tested experimentally. The antenna operates over a 4.0-40 GHz (164% fractional bandwidth) range with a return loss of 10 dB and voltage standing wave ratio (VSWR) < 2. The designed monopole antenna is of dimensions 28.1 mm × 17.1 mm with an electrical size of 0.37 λ × 0.23 λ at 4 GHz frequency. The antenna is fabricated on FR-4 substrate with a dielectric permittivity of 4.4, loss tangent of 0.02, and a thickness of 1.4 mm. The designed antenna exhibits nearly omnidirectional radiation patterns over the entire impedance bandwidth with more than 2.8 dB peak gain for the entire frequency range and 75% of average radiation efficiency. The presented antenna can be used in UWB communications along with C-band, X-band, Ku-band, K-band, Ka-band, WLAN, and future wireless applications.