Design of a Compact and Wideband Monopole Antenna

In this paper, a compact and wideband monopole antenna with vertical polarization is proposed. The antenna has a top loading and a layer of dielectric material to obtain impedance matching. Four vertical substrates have meandered lines on the front to decrease operating frequency and patches on the back to suppress resonances during the wide frequency band. The proposed antenna provides a VSWR less than 2.5 from 0.2 to 1.27 GHz with a bandwidth of 6.35:1. The design has a diameter of
$0.116\lambda_{\max}$
and a height of
$0.093\lambda_{\max}$
, where
$\lambda_{\max}$
is the wavelength corresponding to the lowest operating frequency of the antenna. The proposed model obtains a realized gain from 1.2 to 6 dBi and its total efficiency is above 80% across the bandwidth with nearly omnidirectional far-field radiation patterns.