Synthesis Approach to Planar Filter Design Using New Cascade Hybrid Triplet Block With Arbitrary-Placed TZ Pair

A new low-pass prototype, i.e., cascade hybrid triplet (CHT), is proposed in this article. This triplet, as a synthesis building block, offers two arbitrary-placed transmission zeros (TZs) to suppress the target frequency area or produce a complex TZ pair to flatten the group delay. The CHT can be used to accurately synthesize and design three types of real circuit configurations, i.e., double-dan...