Abstract:
A ring-hybrid directional combiner of a folded structure having LPF(Low Pass Filter) property is provided to reduce the size of the combiner by compounding an LPF of electric length of 1/4 lambda in an equivalence circuit. A ring-hybrid directional combiner of a folded structure having LPF property includes a substrate and first or sixth microstrip railway line units(21,26). The substrate is made of an insulating material. The first or sixth microstrip railway line units(21,26) is generally arranged in a shape of a ring and has first and second transmission railway lines(11,12), an LPF block(13). The first and second transmission railway lines(11,12) with electric length of l/4 lambda are generally arranged on the substrate in a shape of an arc. The LPF block(13) is connected to the first and second transmission railway lines(11,12) and are arranged toward the center of the combiner. A first output port(2), an input port(1), a second output port(3), and an isolation port(4) are arranged in a radial shape with an angle of 60 degrees on a standard of the center of the combiner.
Abstract:
A low pass filter unit having a coupling line with a hairpin structure and a ring-hybrid type directional coupler using the same are provided to reduce a size by minimizing an area of a ring portion of the ring-hybrid type directional coupler. A low pass filter unit includes first and second transmission lines(11,12) and a plurality of coupling lines(21-24). The first and second transmission lines are connected to an adjacent low pass filter unit. The coupling lines are positioned between the transmission lines. One ends of first and second coupling lines and third and fourth coupling lines are connected respectively. Other ends of the second and third coupling lines are connected to each other. The first and second coupling lines and the third and fourth coupling lines face each other in parallel in a hairpin structure. One end of the first transmission line is connected between the first and second coupling lines. One end of the second transmission line is connected between the third and fourth coupling lines.