What is a 4-port differential phase-shifted pulse high-power waveguide isolators?

The 4-port differential phase shift isolators is a combined waveguide device. When the microwave signal passes through the isolator, it can be transmitted with low loss in the forward direction and has high isolation in the reverse direction. It is composed of a 3dB combiner/divider, a parallel ferrite 90° non-reciprocal phase shifter, and a folded double T combiner/divider connected through flanges. As shown in the figure below, when the microwave signal is input from port 1, one part is divided into two parts after passing through the 3dB combiner/divider, and the phase difference is 90°. The two signals propagate in the two waveguide cavities of the ferrite phase-shifting section. Under the influence of external magnetic field, through reasonable selection of ferrite magnetic moment, size, position, etc., and utilizing the non-reciprocal characteristics of microwave signal propagation in microwave ferrite, a 90° non-reciprocal differential phase shifter can be obtained . In this way, when the two signals pass through the phase shifter, two microwave signals of equal amplitude and phase will be obtained at the folded double T. Based on the known microwave transmission characteristics of the folded double T, these two microwave signals of equal amplitude and phase are synthesized. The output is from port 2, and the isolation port is port 4. From the microwave transmission characteristics of the bridge, it can be seen that the microwave signal input at port 1 is isolated at port 3. Therefore, in general, the microwave signal input from port 1 must be output from port 2, and ports 3 and 4 are isolated ports. , Similarly, if the microwave signal is input from port 2, it must be output from port 3, and ports 1 and 4 are isolated ports. When used in the system, connect the waveguide high-power load to port 3, and connect the waveguide matching load to port 4. A waveguide high-power isolator is formed, with 1 port connected to the transmitter and 2 ports connected to the directional coupler, which can realize one-way transmission of microwave energy, effectively protect the transmitter, and function as an 4-port differential phase shift isolators.