Patent ID: 9160044
Filing Date: 2015-10-13
Classification: H01P

Abstract:
1. A frequency variable type millimeter waveband filter comprising: a first waveguide which has a transmission lane having a size allowing electromagnetic waves in a predetermined frequency range of a millimeter waveband to propagate in a TE10 mode; a second waveguide which is formed such that a first transmission line which has a size greater than the outer size of the first waveguide allowing the electromagnetic waves in the predetermined frequency range to propagate in the TE10 mode and receives one end of the first waveguide at a gap from the outer circumference of the first waveguide and a second transmission line having the same size as the transmission line of the first waveguide are arranged concentrically and successively; and a pair of electric wave half mirrors which have characteristics to transmit at part of the electromagnetic waves in the predetermined frequency range and to reflect a part of the electromagnetic waves, one of the electric wave half mirrors being fixed to the transmission line of the first waveguide, and the other electric wave half mirror being fixed to the second transmission line of the second waveguide, wherein the first waveguide is relatively moved with respect to the second waveguide such that the interval between the pair of electric wave half mirrors is changed, and an electromagnetic wave at a resonance frequency to be determined by the interval of the pair of electric wave half mirrors from among the electromagnetic waves in the predetermined frequency range is selectively transmitted, the second waveguide includes a first transmission line forming body which has a plate-shaped portion having a uniform thickness, the plate-shaped portion having a through hole which is formed in a thickness direction to form the first transmission line, and a second transmission line forming body which has a plate-shaped portion having a uniform thickness, the plate-shaped portion having a through hole which is formed in a thickness direction to form the second transmission line, and the first transmission line forming body and the second transmission line forming body are formed in a state where the plate-shaped portions overlap each other such that the through holes are arranged concentrically and successively.