| 摘要 |
PURPOSE:To obtain a branching filter which is small-sized and low in loss, by forming it with a directional coupler by one set of main waveguide and sub-waveguide coupled through the holes where a dielectric has been inserted respectively whose band of strong degree of coupling is narrow and other band is weak in degree of coupling. CONSTITUTION:The main waveguide 2 and the sub-waveguide have a common wall 20 on the surface E, and coupling holes 10, 10' are provided in it. Into the coupling holes 10, 10' are inserted the dielectric whose space is 1/4 of the wavelength in the main waveguide and the sub-waveguide of the branching frequency, and whose thickness is 1/4 of the wavelength in the coupling hole tubes of the branching frequency. And a signal of the frequency component conforming to the band which is able to take a strong degree of coupling in the coupling holes 10, 10' among the input signals having the frequency components of f1+f2+...fN is fetched from the terminal 11 through the waveguide 2, the coupling holes 10, 10' and the waveguide 6. |
