The scheme uses HFSS software to optimize the simulation design of the structure, and produces and measures a sample of the microstrip coupler used in the L-band for maritime satellite communication. The coupler sample is 51% smaller than the traditional double-branched directional coupler. The measured results agree well with the simulation results, which verifies the feasibility of the scheme. 0 Preface In recent years, communication technology has made rapid and rapid development, and microwave communication equipment has also developed. Today, communication devices tend to be miniaturized and portable, which places higher demands on the size reduction of passive devices in communication devices. The directional coupler has a simple structure and good directivity, and has been widely used in microwave communication. The type of directional coupler is divided into microstrip type, waveguide type and coaxial type, and there are branch line coupling, microstrip parallel coupling line coupling, and small hole coupling. Conventional microstrip directional couplers cannot overcome the disadvantages of large area, thus limiting their application in portable microwave devices. At present, the miniaturization of directional couplers has become a hot topic. By compensating the capacitance, the directionality of the coupler is improved and the size is reduced. 2 The miniaturization of the microstrip hybrid ring is realized by introducing a plurality of open branches; 3 the miniaturization is realized by the T-equivalent method; The fishbone shape equivalent of the main line, the sub line, and the coupling line is miniaturized, and the T-type equivalent center overlap problem is avoided. But 3-4 is only a theoretical simulation, and does not take into account the coupling effect of the actual microwave device. Based on the previous research results, this paper proposes a miniaturized design scheme of microstrip double-branch directional coupler, which effectively solves the T-type equivalent center coincidence problem and the fishbone shape of the main line, the auxiliary line and the coupled line. The equivalent coupling distortion is a serious problem. The HFSS software was used to simulate and optimize the design, and the physical test was made. 1 Miniaturized design of directional coupler The structure diagram of the traditional microstrip double-branch directional coupler is shown in Figure 1. The length of the branch line and its spacing are all 1 center phase wavelength. The characteristic impedance of the input and output ports is Z0, the characteristic impedance of the AB segment and the DC segment is 2 Z0 , and the characteristic impedance of the AD segment and the BC segment is Z0. Since 1 has given a detailed explanation of the principle and design formula, this article will not repeat them. Shangchai Generator Set,Power Generator,Electricity Generator,Output Type Generator Yangzhou Hengyuan Electromechanical Equipment Co., Ltd. , https://www.lchypower.com