An UWB microstrip feeding quasi circular antenna

We present the analysis of a quasi circular planar antenna for UWB applications. Analysis includes comparison of coplanar and microstrip feeding. Evolution from the circular antenna requires modifications in the structure and ground plane to soften the edges obtaining improvements in the antenna parameters agreeing with the theory proposed by John Kraus. Evolution is performed for a circular antenna with a design frequency of 4.5 GHz with a bandwidth of approximately 20 GHz. The antenna feeding impedance is proposed as 50 ohms, built over a substrate of RF35-A 0.762 mm × 35 mm × 50 mm. The improvements obtained are reflected in the number of resonances of the antenna throughout the operating bandwidth.