Research And Desigh Of Waveguide Directional Coupler

The directional coupler is a directional passive microwave device, often widelyused in microwave and millimeter-wave domain, for example, the power monitoringsystem, the measurement system, the distribution and synthesis of power system. Inrecent years, with the change of the processing of the coupler, the directional couplergradually become an indispensable element in the communication system. In passivecircuit, the directional coupler is mostly used in filters and matching network. In activecircuit, it is mainly used in the phase shifters, mixers, balanced amplifiers, attenuators,etc.There are many types of directional coupler and they have great difference on thestructure and principle. In recent years, microstrip and stripline directional coupler hasdeveloped rapidly and widely, because of its small size, good performance and easyprocessing, but such couplers are commonly exposed to low power. The waveguidecoupler has high power capability and wide operating bandwidth, which often used inhigh-power system. In this paper, we mainly research the directional waveguide coupler,including single-hole directional coupler and multi-hole directional coupler. Thedirectional waveguide coupler we designed has good performance, and by testing, it isproved to have more advantages and practical applicability.In this paper, by studying the hole coupling theory, we learn about the workingprinciple of single-hole and multi-hole directional coupler. Based on the traditionaltheory of waveguide directional coupler, we make a step-by comparison of the structureparameters of single-hole waveguide directional coupler, and make a conclusion aboutthe relationship between the coupling performance with the change of structureparameters. After this, we promoted a new waveguide directional coupler innovativelyand improve its coupling form. We raise triangular and rectangular coupling structure.By the simulation and optimization on software, we designed a compact waveguidedirectional coupler which has wide working frequency band as well as betterdirectionality and has been applied for patent. The later test verified its advantages andpracticality. Through this work, an innovate design of waveguide directional coupler ispresented, which provides a new idea or method for the design of waveguide directionalcoupler. By measuring, such couplers can be used in directional system.