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Published on: August 30, 2012
Crossed waveguide directional couplers for high power applications.
1Faculty of Engineering and Surveying, University of Southern Queensland, Toowoomba, Qld., Australia 4350.
Summary
Directivity in microwave couplers can be improved by using narrow crossed slots for coupling apertures. This study extends small aperture coupling theory and validates it with measurements on a Moreno coupler.
Area of Science:
- Electromagnetics and Microwave Engineering
- Applied Physics
Background:
- The Moreno coupler is a type of microwave directional coupler.
- Small aperture coupling is a key phenomenon in microwave device design.
Purpose of the Study:
- To review and extend the small aperture coupling theory for broad wall to broad wall couplers.
- To develop a design procedure for narrow wall to broad wall couplers.
- To demonstrate the accuracy of the small aperture theory through experimental validation.
Main Methods:
- Theoretical analysis of small aperture coupling, focusing on polarizability ratios.
- Development of a design procedure incorporating wall proximity effects.
- Experimental measurements on manufactured Moreno and narrow wall to broad wall couplers.
Main Results:
- A lower limit on directivity is determined by the ratio of magnetic to electric polarizability of coupling apertures.
- Very narrow crossed slots were identified as a method to improve directivity.
- Experimental results confirm the accuracy of the extended small aperture theory and the design procedure.
Conclusions:
- Small aperture coupling theory accurately predicts the performance of microwave couplers.
- Optimizing aperture geometry, specifically using narrow crossed slots, enhances coupler directivity.
- The developed design procedure effectively accounts for wall proximity effects in coupler design.
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