A unique coplanar-waveguide (CPW)-fed circularly polarised square slot antenna with enhanced impedance bandwidth (IBW) is presented. The antenna structure includes a pair of rectangular-shaped notches located at two opposite corners of the slot for achieving a significantly enhanced IBW of 12.06 GHz (2.76-14.82 GHz), and a pair of reverse L-shaped ground arms in the slot for realising circularly polarised radiation with 1.86 GHz (4.27-6.13 GHz) bandwidth. This proposed technique has the advantages of covering the whole of the ultra-wideband spectrum (3.1-10.6 GHz), an average gain of 3 dBi and a reduced antenna size of 25 × 25 × 0.8 mm 3 .

This article presents a novel and compact circularly polarized square slot antenna (CPSSA) that operates across 2.93–11.43 GHz with an impedance bandwidth of 118% for VSWR ≤ 2. This makes the antenna feasible for UWB applications requiring high data rate transmission. The antenna with an annular radiation patch is fed through a coplanar waveguide and includes two inverted‐L shaped ground arms at two opposite corners of the slot to excite two orthogonal resonant modes for circular‐polarization (CP) radiation. A semicircular stub is embedded in the feed‐line to enhance its impedance bandwidth. The antenna exhibits CP bandwidth of 22.2% across 4.87–6.09 GHz, which incorporates the WLAN band. In addition, the antenna has a significantly smaller volume of 25 × 25 × 0.8 mm3. The measured and simulated results confirm the usefulness of the antenna for practical applications. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:229–233, 2014

A compact CPW-fed printed monopole slot antenna is presented for ultra-wideband (UWB) applications. The antenna comprises of a dome-shaped radiating element in which embedded is an open-loop inverted triangular-shaped slot (TSS). The antenna is fed through a coplanar waveguide to provide an ultra-wide impedance bandwidth of 8.95 GHz (2.58–11.53 GHz) which corresponds to a bandwidth ratio of 1:4.46 for VSWR <2. The antenna possesses a notch band functionality to filter out interfering C-band signals like wireless local-area network (WLAN). The notch band frequency is determined by physical parameters defining the TSS that allows fine control of the notch's location. The proposed antenna also possesses a flat gain response expect at the notched band and occupies a relatively small volume of 25 × 25 × 0.8 mm3 for ease of system integration.