Two novel very small monopole antennas having frequency band notch function using DGS for UWB application

In this article, we describe two novel types of coplanar wave-guide (CPW) fed monopole and an asymmetric coplanar strip (ACS) fed half monopole UWB antennas to cover the ultra-wideband frequency operation. The proposed antennas consist of a hexagonal shaped patch with small volume (18.4×21.5×1mm3) and (11.4×21.5×1mm3), respectively. The band-rejection operation achieve at the WLAN (5.15–5.85 GHz) band by adding defected ground structure (DGS) or slit in the ground plane. The antennas are fabricated on FR4 substrate with a relative dielectric constant of 4.4 and thickness of 1 mm which are fed by a 50Ω line. The antennas are investigated numerically and experimentally for their impedance matching properties, frequency notched characteristics, and radiation performances. The measured frequency response shows an impedance bandwidth of 13 GHz or 130% over 3–16 GHz for VSWR <2<2.