Narrowband Hairpin Bandpass Filter for 4G LTE Applications

Narrowband bandpass Filter plays an important role in modern wireless communication systems specially in the sub 6GHz space. In many cases, transmitted and received signals must be filtered at a certain center frequency with specific bandwidth limitations asper specifications. This research article represents the principle of microwave filter design, fabrication, and performance evaluation of bandpass filter design using the fundamental hairpin resonator structure. It is proposed to design a fifth-order Chebyshev bandpass filter with center frequency at 2.01 GHz using two different FR4 and Arlon 25N substrates separately. The simulated designs are implemented using the fullwave electromagnetic solver Genesys and fabricated on both substrate materials. We observed the accurate and reasonable filter parameters like return loss and insertion loss S11, S21 in both simulation and measurements. The design specifications bandwidth of400MHz, (-30dB, -1.4dB) and (-20dB, -2.5dB) of return, insertion losses were obtained respectively on Arlon 25N, FR-4 materials respectively. The designed filter has multiple potential applications for 4G LTE bands.