Title :
Computer-aided design of slit-coupled H-plane T-junction diplexers with E-plane metal-insert filters
Author :
Dittloff, Joachim ; Arndt, Fritz
Author_Institution :
Microwave Dept., Bremen Univ., West Germany
Abstract :
The rigorous field-theory-based design of a class of rectangular waveguide slit-coupled H-plane T-junction diplexers utilizing E-plane metal-insert filters is described. The filter elements allow low-cost manufacturing by accurate and inexpensive metal-etching techniques. The design method is based on a field expansion in suitably normalized eigenmodes which yields the modal scattering matrices of the three key building blocks used: the E-plane metal-insert section, the H-plane iris discontinuity, and the H-plane T. The theory includes the finite thickness of the diaphragms as well as the higher order mode interaction of all discontinuities within the complete diplexer structure. Computer-optimized design data for diplexer examples in Ku-band (12-18 GHz) and E-band (60-90 GHz), designed for more than 23-dB common port return losses, are given. The theory is verified by measured results for a five-resonator Ku-band diplexer.<>
Keywords :
CAD; S-matrix theory; electronic engineering computing; microwave filters; passive filters; rectangular waveguides; waveguide components; 12 to 18 GHz; 23 dB; 60 to 90 GHz; CAD; E-plane; H-plane; H-plane iris discontinuity; Ku-band; T-junction diplexers; common port return losses; computerised-optimised design data; diaphragm thickness; field expansion; field-theory-based design; higher order mode interaction; low-cost manufacturing; metal-etching techniques; metal-insert filters; modal scattering matrices; normalized eigenmodes; rectangular waveguide; slit-coupled; Arm; Design automation; Design methodology; Dielectric losses; Filtering theory; Iris; Microwave filters; Rectangular waveguides; Scattering; Transmission line matrix methods;
Journal_Title :
Microwave Theory and Techniques, IEEE Transactions on
