Our research goal is to reduce the mass and size of such filters by the adoption of a TM dual-mode cavity loaded with a high-permittivity cylinder.
Two papers about this topic have been already published:
"Ultra-compact pseudoelliptic waveguide filters using TM dual-mode dielectric resonators" Microwave Conference Proceedings (APMC), 2011 Asia-Pacific
"Ultra-compact filters using TM dual-mode dielectric-loaded cavities with asymmetric transmission zeros" Microwave Symposium Digest (MTT), 2012 IEEE MTT-S International
Our research is now focusing on the implementation of dual band and reconfigurable filters by using such technlology