Design of 3D Printed Coaxial Sleeve Bandpass Filter

This paper presents a new design concept of coaxial sleeve bandpass filter (BPF), which is based on two different resonators. The first resonator is a dual-mode coaxial cavity achieved by adding a sleeve to a conventional coaxial metal post, while the second one is a single-mode resonator. By cascading them together, the fundamental modes of two cavities are used to form a passband. This special configuration and port position can introduce two transmission zeros above the passband, which leads to high selectivity. To verify the design concept, a BPF operating at 2.06GHz with the bandwidth of 160MHz is designed and simulated.