A new prototype for the design of side-coupled coaxial filters with close correspondence to the physical structure

This paper presents a new mixed lumped-distributed prototype for the design of coaxial filters, in which the cavities are coupled via their side-walls. The element values are explicitly given in terms of the well-known Cohn´s direct coupled cavity prototype. The main feature of the proposed model is its one-to-one correspondence to the physical structure, making a design feasible without additional optimizations or expensive tuning. The circuit has been employed in the design of several diplexers, obtaining excellent results.