Rentian Science Park has been built in Linzhang, Handan, and has a 2000 square meter Hebei Mobile Communication Antenna Technology Research Center with complete R&D equipment, including spectrum analyzer, signal generator, power splitter, RF cable, EMI test receiver, log periodic antenna, microwave anechoic chamber and other antenna R&D equipment. A special R&D team has been established. The team leader is Professor Huang Yi, a distinguished expert of Hebei Hundred Talents Plan, and the team members are 6 in total, Three of them are senior engineers, ensuring their research and development capabilities. The project is expected to invest 1 million yuan in research and development for new products. 1. How to achieve dual band coupling? 2. How to reduce product size while ensuring signal transmission efficiency? 3. The addition of new frequency bands, compatibility with the original frequency band, and effective signal transmission. 1. Utilizing dual frequency impedance converters to replace traditional quarter wavelength impedance converters to achieve dual frequency bands of couplers. 2. By improving the frequency ratio range, loading open branch lines on the coupler branch lines, reducing the coupler size, introducing stepped impedance lines to increase design freedom, and improving the working bandwidth of dual frequency couplers, the expected goals are achieved. 3. Through simulation design and prototype trial production, a dual frequency coupler that can be compatible with the 5G frequency band was ultimately designed. Develop a new type of universal coupler for mobile communication systems that meets and includes the transmission needs of mobile communication lines in the 5G communication frequency band. Reduce the investment cost of communication systems. In RF signal systems, directional couplers are applied in information extraction, power allocation, multi-channel coupling, power monitoring devices in signal generators, and microwave receivers during signal transmission. The project team has developed a microwave component that is used to allocate or synthesize microwave signal power and has directional coupling characteristics. It is composed of appropriate coupling structures between the main and secondary transmission lines (referred to as the main and secondary lines). With the application of the new generation of mobile communication 5G systems, various types of couplers that were previously used are no longer applicable due to the increase in application frequency bands and the expansion towards high frequencies. In response to this issue, the project team plans to design a new coupling structure between the main and secondary transmission lines (referred to as the main and secondary lines) of the coupler, and develop a new coupler that can include both the original application frequency band of mobile communication and the new application frequency band of 5G system, replacing the old with the new and reducing repeated investment in equipment.