Microstrip-based ultra-wideband composite BPF with short-circuited stubs

In this paper, the design and realization of microstrip-based ultra-wideband (UWB) composite bandpass filter (BPF) with short-circuited stubs is presented. The BPF is compositely constructed from the step impedance lowpass filter (LPF) and the optimum distributed highpass filter (HPF). Prior to the realization, the performances of filter and its physical dimension are investigated numerically to obtain the optimum design. The BPF is deployed on a grounded FR4 Epoxy dielectric substrate with the thickness of 0.8mm and the dimension of 25mm x 25mm. From the measurement result, it shows that the realized UWB composite BPF has 3dB bandwidth response of 10.03GHz ranges from 1.86GHz to 11.89GHz.