A microstrip filter based on transversal section of parallel-coupled line with U-shaped slot for wideband and notch response

In this paper, a wideband transversal filter with notch is proposed. A parallel-coupled line with U-shaped slot is proposed as transversal section. Phase performance is studied and found that it is almost unchanged compared to the traditional ones. But U-shaped slot introduces a notch within the passband. To validate this design, a wideband filter with passband from 3.2 GHz to 11 GHz is designed and a notch of 9 GHz is realized because of the introduction of U-shaped slot underneath the parallel-coupled line.