Patent ID: 8779995

Claim:
A phase shifter, comprising: a high-frequency waveguide including first and second conductors disposed facing each other at a spacing of less than λ 0 /2 when the free space wavelength of the operating frequency of a high-frequency signal is λ 0 , a ridge that protrudes from one of the first and second conductors toward the other in a waveguide formation portion formed between the first and second conductors, and that is formed extending along the waveguide formation portion, a plurality of columnar protrusions with a height of λ 0 /4 and disposed at a spacing of less than λ 0 /2 on at least one of the first and second conductors on the outside of the waveguide formation portion and to the outside of the ridge, and a movement mechanism configured to relatively move the first and second conductors so as to vary a length of the waveguide, wherein the first and second conductors include two first conductors and two second conductors, wherein an intermediate conductor is constituted by bringing together two of the faces of the two first conductors, wherein the two second conductors are disposed on the front and rear face sides of the intermediate conductor, respectively, wherein a linking path goes through the two first conductors constituting the intermediate conductor, and wherein the intermediate conductor is able to move relatively with respect to the two second conductors disposed on the front and rear face sides of the immediate conductor, respectively.