Design of an ultra-wideband monopole antenna with WiMAX, C and wireless local area network band notches

Abstract

A compact ultra-wideband (UWB) coplanar waveguide (CPW)-fed printed monopole antenna with single and double band-rejection characteristics are investigated. The antenna has is staircase shaped and is fabricated on a FR4 substrate with an area of 19.5×21×1 mm3. To generate single- and dual-band-notched characteristics, two symmetric and asymmetric quarter wavelength spiral slits cut at the patch are utilised. The simulated and measured results including impedance matching, radiation patterns and gain results are investigated. The measured frequency results show an impedance bandwidth of 8.4 GHz over 2.6–11 GHz for a voltage standing wave ratio less than 2 with two eliminated bands centred at 3.8 and 5.5 GHz to reject the wireless local area network band (5.15–5.85 GHz) and the WiMAX band (3.3–3.6 GHz), along with a major part of the C band (3.7–4.2 GHz). The omni-directional radiation patterns of the fabricated antenna are presented, which show that this design antenna is a good candidate for various UWB applications. The measured gain variation is less than 3 dB over the operating frequency band.