Nonuniform transmission line codirectional couplers for hybrid MIMIC and superconductive applications
Abstract
A new design approach for thin-film codirectional quadrature couplers and their applications is described. An in-depth analysis and semi-empirical design curves are presented for these couplers. Forward-wave coupling is achieved by making use of the difference between even- and odd-mode phase velocities. Modified nonuniform codirectional couplers with a dummy channel for continuously decreasing or increasing taper and employing wiggly, serpentined and smooth coupled edges have been designed and tested. It is found that a wiggly coupler can achieve a 50% length reduction compared to a smooth-edge coupler. A further 60% length reduction compared to a wiggly coupler is achieved by a serpentine coupler. Coupler performance for wiggly and serpentined configurations is computed by choosing a realizable phase velocity function for a given coupler length. Either constant 90deg or - 90deg phase shift is possible with these couplers giving significant design flexibility in some applications. The results for a K(sub u)-band Sigma-Delta Magic-T circuit employing a 0 dB wiggly coupler and a - 3 dB smooth-edge coupler are also presented.
- Publication:
-
IEEE Transactions on Microwave Theory Techniques
- Pub Date:
- March 1994
- DOI:
- 10.1109/22.277434
- Bibcode:
- 1994ITMTT..42..407U
- Keywords:
-
- Circuits;
- Computer Aided Design;
- Couplers;
- Electric Networks;
- Magic Tees;
- Network Analysis;
- Nonlinear Systems;
- Superconductors;
- Transmission Lines;
- Phase Shift;
- Phase Velocity;
- Quadratures;
- Serpentine;
- Thin Films;
- Electronics and Electrical Engineering