Ultra wideband CPW fed modified ring antenna

This paper presents a coplanar waveguide (CPW) fed modified ring antenna that achieves a VSWR < 2 and uniform radiation patterns over a 3:1 bandwidth ranging from 5 GHz to 15 GHz. The antenna demonstrates an omni-directional radiation pattern in azimuth plane and symmetric radiation pattern in elevation plane. This characteristic is ideal for mobile wireless communication applications. The simple antenna structure, which is circularly patch connected to CPW feed line through the triangle transition, has an advantage of easy adjustment for the input impedance matching. The predicted results are compared with measured data and they show a good agreement.