On the Simple-ｌoop Hybrid Ring（Part 4）−Simple-loop Hybrid Ring of Double-Peak Characteristics−

The simple-loop hybrid ring used in the microwave band has the simplest structure among various kinds of hybrid circuits. But its electric characteristics are worse than those of hybrid circuits. There are various methods for improving the bandwidth. By connecting two unsymmetrical hybrid rings in cascade，and making the image immitance matrices diagonal，a perfect matching and a perfect isolation will be obtained at the ports and between the ports of the circuits respectively at any frequency （electrical angle）of near the center frequency. The operating characteristics of the circuit i.e. the isolation，the reflection coefficient and the phase difference between the output voltages show double-peak characteristics and "W" characteristics respectively.