Wideband BPF composed of planar inverted-F shaped for S-band frequency application

This paper deals with the design and implementation of wideband bandpass filter (BPF) composed of planar inverted-F shaped. The filter is intended to have working bandwidth more than 1GHz at S-band frequency for radar application. The choice of inverted-F shape is due to the ability to provide flexibility characteristics in impedance matching and working bandwidth. Prior hardware realization and measurement, the performance of filter is numerically investigated to obtain the optimum design. The prototype is then realized by constructing 2 identical elements of planar inverted-F shaped which every single element is etched on a 1.6mm thick flame retardant (FR) glass-reinforced epoxy dielectric substrate with the dimension of 24mm in length and 33mm in width. From the measurement, the realized filter shows a good agreement in frequency responses comparable to the simulated result with minimum insertion loss of 1.17dB within the passband area and 10dB less of return loss in the frequency range from 1.92GHz to 3.21GHz.