5G hairpin bandpass filter

In this paper, Hairpin Bandpass Filter (HPBF) is designed, simulated and fabricated at two 5G low-frequency bands: 3.7 GHz-4.2 GHz and 5.975 GHz-7.125 GHz. This filter will be a part of our 5G narrowband/ Ultra Wide Band (UWB) reconfigurable antenna project that plays a significant role in the recent wireless networks, such as Cognitive Radios (CRs). Through the two frequency bands, the filter resulted in good matching and transmission responses with enhanced bandwidth. The measured reflection coefficient of the proposed HBPF, S₁₁ is <-10 dB and <-11.66 dB through 3.45 GHz – 4.25 GHz and 5.62 GHz – 7.6 GHz, respectively. However, the transmission coefficient, S₁₂ is around-1.5 dB and – 1.17 dB at the center frequencies F_C = 3.75 GHz and 6.61 GHz, respectively. In this paper, the High-Frequency Structure Simulator (HFSS) software is used to carry out the simulation. The full-wave simulation results are validated with the hardware measurements.