A Millimeter Wave Triband Bandpass Filter Using Stub-Loaded Hexagonal Patch with Complementary Spiral Resonator

In this paper, a triband bandpass filter has been proposed for millimeter wave and 5G applications. The filter design is progressed using a complementary spiral resonator superimposed on a hexagonal patch measuring about 7 mm × 4.2 mm × 0.8 mm. employing Rogers 5880 as substrate with εr = 2.2. This triband filter is highly selective with sharp rejections emulating bandwidths of about 1.3 GHz, 2.5 GHz, and 1.8 GHz capable of supporting millimeter wave and 5G communications. The qualifying parameters of filter-like insertion loss have been realized between −0.6 dB and −0.16 dB and return loss between −19.12 dB and −28 dB for the corresponding three bands. Moreover, the performance attainment of the filter has been verified from the surface current distribution of the filter. The filter resonates at millimeter wave frequencies of 29.6 GHz, 32.5 GHz, and 35.8 GHz portraying a triband response. The simulated and measured results substantiated very well with each other.