Wideband printed monopole antenna for application in wireless communication systems

Abstract

Empirical results of an electrically small printed monopole antenna is described with fractional bandwidth of 185% (115 MHz–2.90 GHz) for return-loss better than 10 dB, peak gain and radiation efficiency at 1.45 GHz of 2.35 dBi and 78.8%, respectively. The antenna geometry can be approximated to a back-to-back triangular shaped patch structure that is excited through a common feed-line with a meander-line T-shape divider. The truncated ground-plane includes a central stub located underneath the feed-line. The impedance bandwidth of the antenna is enhanced with the inclusion of meander-line slots in the patch and four double split-ring resonators on the underside of the radiating patches. The antenna radiates approximately omnidirectionally to provide coverage over a large part of VHF, whole of UHF, entire of L-band and some parts of S-band. The antenna has dimensions of 48.32×43.72×0.8 mm3, which is corresponding with the electrical size of 0.235λ_0×0.211λ_0×0.003λ_0, where λ_0 is free-space wavelength at 1.45 GHz. The proposed low-profile low-cost antenna is suitable for application in wideband wireless communications systems.