Study of planar ultrawide-band antennas

Three kinds of novel planar ultrawideband antennas are presented in this paper. The first one is the planar circular disc monopole antenna. The radiator, ground plane and the feeder equipment of the antenna are placed on the same plate. The special structure reduces the spatial volume. The second one is the composite triangle monopole antenna, which is composed of three similar triangle metal plates. The simulation results show that the antenna not only has wide impedance frequency band, but also takes up smaller space comparing with triangle monopole. The third one is the strip-loaded wide slot antenna with a circular slot. It is fed by coplanar waveguide. The antenna can realize good bandwidth performance. The novel antennas are suitable for the wireless communications, satellite communications and mobile communications systems with good prospects.

1. Introduction

There has been considerable research effort put into ultrawideband antenna with the development of UWB technology. In recent years, monopole antennas are the focus of UWB antenna. Several broadband monopole configurations, such as circular, square, and elliptical have been proposed so far [1]. However, they are not planar structures as the ground planes are perpendicular to radiators. On the other way, planar wide slot antenna (WSA) with omnidirectional radiation patterns is one of the most attractive candidates for UWB antennas [2]. Thus, many WSAs with different slot shapes such as rectangular, circular, arc-shape, and various feed shapes such as T, cross, fork–like, bowtie, radial stub, pi, double-T, and rectangular were presented. Moreover, some special techniques are also applied for wider bandwidth, such as adding round corners [3].