An integrated T-septum waveguide diplexer for compact front-end applications

A novel T-septum waveguide diplexer for compact integrated front-end applications in modern communication systems is introduced. This 8.74/10.14 GHz X-band design is for 4% channel bandwidths. The size reduction is predominantly achieved by utilizing T-septum filter technology, which reduces the dimensions of a typical waveguide filter by a factor of four to five. Moreover, a considerably improved stopband behavior toward higher frequencies is obtained. Together with a height-reduced waveguide E-plane T-junction, the overall diplexer dimensions are less than (30 mm)/sup 3/. The computer-aided analysis and design are based on mode-matching techniques and optimization procedures, respectively. The channel filters are separately synthesized and fine-tuned by a final optimization to meet diplexer specifications. The theory is verified by measurements for the example of an X-band T-septum filter configuration.<>