The Design Of Double-ridge Waveguide Broadband Coupler

The directional coupler is applied widely to Microwave Devices in Microwave System, for example there are all directional couplers in power measurement, microwave transmission system, reflect-meter, double stitch and duplexer. As the directional coupler has a wide use under different conditions. The directional coupler has a great many kinds and the otherness is large. In structure the coupler can be made in wave-guide strip-line microcircuit and coaxial axis. In coupling mode small aperture coupling is used most widely.Home and abroad the research of coupler is ripe, especially the research of wave-guide coupler is Pinakamatagal and the kinds are the most. However, the researches of double-ridge waveguide directional coupler are few. Modern microwave systems have a trend that more and more wide band is needed. Because the request of bandwidth is more and more wider in modern electronic system measurement system and other microwave systems, the trend promote the research of more wide band microwave devices, so the more wide band research has a greatly significant. Also this trend also promotes the research of coupler. In this article we will use the different principles of design of waveguide directional coupler for reference, we adopt the form of double-ridge waveguide to design high-power and broadband directional coupler. (Here we use the WRD650 standard form)As we know that the double-ridge waveguide has lower cut-off frequency than rectangular waveguide, the double-ridge waveguide also has wider single model bandwidth and lower impedance. So the double-ridge form has superiority. In the design first we adopt the circular holes coupling mode to acquire advantages and disadvantages in this mode. Then we change to adopt unsymmetrical cross hole to design the coupler. Comparing cross hole and circular hole we can find that the unsymmetrical cross hole is better than circular hole. By theory analysis, numerical calculation and electromagnetism simulating software we compare the results and improve the property. For the perfect target we also take several particular actions to improve the capability of double-ridge waveguide coupler.In this article, we have a comprehensive analysis and research to double-ridge waveguide directional coupler. The specific work is as follows:1,First adopting conventional sketched holes to design double-ridge directional coupler, then adopting improving form of unsymmetrical cross holes. Compare the forms, Double-Ridge Waveguide Directional Coupler in the form of unsymmetrical cross hole is superior.2,Analysis the effect when the structure of Double-Ridge Waveguide is changed little, and find the sensitive factors of the coupler indicators.3,Design the converter between the Double-Ridge Waveguide and Coaxial line. Solve matching problem of impedance between Double-Ridge Waveguide and Coaxial line4,By simulation software, simplify the calculation of radius of holes. Only knowing the proportion of hole radiuses, we optimize the best data by simulation software.