Fractal Bandpass Filter Using Y-shaped Dual-Mode Resonator for C-Band Receiver (Research Note)

In this study, a fractal, Y-shaped dual-mode resonator bandpass filter (BPF) with input-output cross-coupling is introduced. A parallel-coupling feed structure with a cross coupling has been used to generate two transmission zeroes (TZs) near the lower and upper cutoff frequency that can effectively improve the passband edge selectivity. Also, a fractal shaped based on conventional diamond and square is located. Current density and equivalent model is also given depending on the odd/even excitation resonance condition. The demonstrated filter with a compact size of 0.5*18.3mm2 exhibits a fractal bandwidth of 67% centred as 6GHz(f0) within the 4 to 8GHz bandwidth and minimum insertion loss of 0.3 dB, maximum return loss of 13,15.7dB and flat group delay around 0.3ns that is candidate for use in commercial communications satellites(C-Band).