Implementation of UWB antenna with bandpass filter using microstrip-to-CPW transition matching

The implementation and experimental results of coplanar waveguide (CPW) UWB antenna with microstrip bandpass filter (BPF) is presented. The designed antenna is a CPW-fed half circular and rectangular shaped monopole antenna. Microstrip BPF with notched WLAN band (5.15-5.825 GHz) is composed of the stepped impedance and stub symmetric structure. For impedance and field matching between CPW antenna and microstrip BPF, the microstrip-to-cpw transition is proposed. Ultra-wideband characteristics of the antenna and filter are retrieved to be simplified by performing impedance and field matching between separately designed UWB antenna and BPF. The measured return loss of UWB antenna module with BPF is more than 11 dB and VSWR is less than 2 for the frequency range between 3 and 10.3 GHz except of WLAN band with the relatively flat antenna gain and radiation efficiency. The overall size of fabricated structure is 64.2 mm × 20 mm × 0.83 mm.