What is 3dB Hybrid Coupler?
3dB Hybrid Coupler is a kind of directional coupler.
When used as a power combiner, the two input signals are connected to each other as isolated ports, while the coupling output and direct output ports are reciprocal If it is used as two outputs without considering the loss, the input signal power is divided into two outputs.
When used as a single port output, the other output must be connected with a matching power load to absorb the output power of the port, otherwise, the transmission characteristics of the system will be seriously affected. At the same time, it will also bring an additional 3dB loss, which will affect the cost and reliability of its active part for system application
Application for 3dB Hybrid Coupler：
3dB Hybrid Coupler is mainly used for combining different carriers in the same frequency band.
Due to the discreteness of the circuit and processing assembly, the isolation of the input port of the bridge coupler is relatively low, so it is not recommended to be used in the combined application between different frequency bands.
To sum up, in the application of different frequency combining, except that the adjacent carrier frequency in the same frequency band (such as the adjacent carrier frequency in the GSM downlink frequency band) can only use a 3dB bridge instead of a duplex/multiplex combiner, it is recommended to give priority to duplex/multiplex combiner in use, so as to improve the performance index of the system and increase the reliability
