A wide-band band-pass filter based on signal-interference techniques

In this paper, a wide-band band-pass filter with sharp-rejection, low insertion-loss is proposed. The filter is consisted of shorted coupled lines and T-shaped transmission lines. Due to two transmission zeroes located at the two edges of the passed band, the band-pass skirts are sharpened. So the selectivity is improved greatly. ABCD matrix is applied to deduce the S-parameters of the filter. Based on the theoretical analysis, a wideband band-pass filter with a fractional bandwidth of 50% (1.5-2.5 GHz) is simulated. Good agreement between the calculated and simulated is observed, verifying the proposed concept.