Top‐cross‐loop improving the performance of the UWB planar monopole antennas

Abstract

AbstractA novel topology of top‐cross‐loop (TCL) is proposed for the CPW‐fed ultra‐wideband (UWB) antenna. It increases the bandwidth of the planar monopole antennas and keeps their good radiation characteristics. Both those properties are required by UWB devices. The topology is convenient for the mass production because it is single‐layer and easy to fabricate. A prototype of the UWB antenna with TCL is designed, fabricated and measured to confirm the advantages of the novel topology. It covers the bandwidth of 91%, a 1.71 GHz increase from the monopole antenna of the same size without TCL. Additionally, the omnidirectional radiation pattern and the low cross‐polarization in the azimuth plane throughout the bandwidth are also achieved. The detailed parametric studies have been performed to characterize the effects of various parameters for optimal performance of the antenna with the TCL topology. A quantitative method—system fidelity factor (SFF)—is utilized to characterize the time domain performance of the antenna. The fabricated monopole with the TCL achieved an SFF of over 0.65 in the measurement and showed low dispersive characteristics in the time domain analysis. Miniaturization of the proposed antenna further reduces the overall size by 27%.