Design of a 5.8 GHz Broadband BPFs with Second Harmonics Suppression Using Open-Stubs

In this paper, integration of a broadband open-stub bandpass filters (BPFs) is presented. The second harmonics can be suppressed by combining the frequency selective coupling structure (FSCS) and quarter-wavelength using Z-transform technique. Newly developed BPFs reduce the size as compared to the conventional one by inserting the inverter between the stubs. Experiment results showed bandwidth of 95% with the center frequency of 5.8 GHz, insertion loss of -0.6 dB and return loss of -14 dB. The designed BPFs can be applied for C-band of satellite communication and intelligent transportation system (ITS) application.