Waveguide device, and antenna device including the waveguide device

Abstract

A waveguide device for use in propagating an electromagnetic wave of a band having a shortest wavelength λm in free space includes: a first electrically conductive member having an electrically conductive surface and a first throughhole; a second electrically conductive member including a plurality of electrically conductive rods each having a leading end opposing the electrically conductive surface, the second electrically conductive member having a second throughhole which overlaps the first throughhole as viewed along an axial direction of the first throughhole; and an electrically-conductive waveguiding wall at least partially surrounding a space between the first throughhole and the second throughhole and being surrounded by the plurality of electrically conductive rods, the waveguiding wall allowing the electromagnetic wave to propagate between the first throughhole and the second throughhole. The height of the waveguiding wall is less than λm/2. The distance between an electrically conductive rod among the plurality of electrically conductive rods that is adjacent to the waveguiding wall and the outer periphery of the waveguiding wall is less than λm/2.

What is claimed is: 
     
         1 . A waveguide device comprising:
 a first electrically conductive member having an electrically conductive surface and a first throughhole;   a second electrically conductive member including a plurality of electrically conductive rods each having a leading end opposing the electrically conductive surface, the second electrically conductive member having a second throughhole which overlaps the first throughhole as viewed along an axial direction of the first throughhole; and   an electrically-conductive waveguiding wall at least partially surrounding a space between the first throughhole and the second throughhole and being surrounded by the plurality of electrically conductive rods, the waveguiding wall allowing an electromagnetic wave to propagate between the first throughhole and the second throughhole, wherein   the waveguiding wall is connected to one of the first electrically conductive member and the second electrically conductive member, and a gap exists between the waveguiding wall and the other one of the first electrically conductive member and the second electrically conductive member.   
     
     
         2 . The waveguide device of  claim 1 , wherein the waveguiding wall is connected to the first electrically conductive member, and the gap exists between the waveguiding wall and the second electrically conductive member. 
     
     
         3 . The waveguide device of  claim 2 , wherein the waveguiding wall and the first electrically conductive member are portions of a single-piece body. 
     
     
         4 . A waveguide device comprising:
 a first electrically conductive member having an electrically conductive surface and a first throughhole;   a second electrically conductive member including a plurality of electrically conductive rods each having a leading end opposing the electrically conductive surface, the second electrically conductive member having a second throughhole which overlaps the first throughhole as viewed along an axial direction of the first throughhole; and   an electrically-conductive waveguiding wall at least partially surrounding a space between the first throughhole and the second throughhole and being surrounded by the plurality of electrically conductive rods, the waveguiding wall allowing an electromagnetic wave to propagate between the first throughhole and the second throughhole, wherein   the waveguiding wall includes a first portion that connects to the first electrically conductive member and a second portion that connects to the second electrically conductive member.   
     
     
         5 . The waveguide device of  claim 4 , wherein,
 the first electrically conductive member and the first portion are portions of a single-piece body; and   the second electrically conductive member and the second portion are portions of another single-piece body.   
     
     
         6 . The waveguide device of  claim 1 , wherein,
 cross sections of the first throughhole, the second throughhole, and the waveguiding wall, as taken along the electrically conductive surface, each include a lateral portion extending in one direction; and   a length of the lateral portion as measured along the one direction is longer than a length of the lateral portion as measured along another direction that is vertical to the one direction.   
     
     
         7 . The waveguide device of  claim 6 , wherein the cross sections of the first throughhole, the second throughhole, and the waveguiding wall, as taken along the electrically conductive surface, each further include at least a pair of vertical portions extending in another direction intersecting the one direction, and the lateral portion interconnects the pair of vertical portions. 
     
     
         8 . The waveguide device of  claim 7 , wherein,
 inner wall surfaces of the first throughhole, the second throughhole, and the waveguiding wall each include at least one projection which projects inward;   the projection is connected to the lateral portion; and   as viewed along the axial direction of the first throughhole, the projection is interposed between the pair of vertical portions.   
     
     
         9 . The waveguide device of  claim 1 , wherein,
 the electrically conductive surface is planar;   the first throughhole extends through the first electrically conductive member perpendicularly to the electrically conductive surface; and   the second throughhole extends through the second electrically conductive member along the axial direction of the first throughhole.   
     
     
         10 . The waveguide device of  claim 1 , wherein, among the plurality of electrically conductive rods, the second electrically conductive member further includes a waveguide member having an electrically-conductive waveguide face opposing the electrically conductive surface. 
     
     
         11 . The waveguide device of  claim 1 , wherein,
 the second electrically conductive member has an electrically conductive surface on a side opposite from the plurality of electrically conductive rods;   the waveguide device further comprises a third electrically conductive member;   the third electrically conductive member includes   a waveguide member having an electrically-conductive waveguide face opposing the electrically conductive surface of the second electrically conductive member, and   a second plurality of electrically conductive rods each having a leading end opposing the electrically conductive surface of the second electrically conductive member, the second plurality of electrically conductive rods being on both sides of the waveguide member; and   the waveguide face opposes the second throughhole at a site on the waveguide face.   
     
     
         12 . The waveguide device of  claim 1 , wherein,
 the second electrically conductive member includes, on a side opposite from the plurality of electrically conductive rods, a second plurality of electrically conductive rods and a waveguide member having an electrically-conductive waveguide face;   the waveguide device further comprises a third electrically conductive member having a third electrically conductive surface opposing leading ends of the second plurality of electrically conductive rods and the waveguide face; and   the second throughhole is open at an end of the waveguide face of the waveguide member or another site.   
     
     
         13 . The waveguide device of  claim 1 , further comprising a further electrically conductive member on a side of the first electrically conductive member opposite from the second electrically conductive member, the further electrically conductive member having a fourth electrically conductive surface, wherein,
 the first electrically conductive member includes   a waveguide member having an electrically-conductive waveguide face opposing the fourth electrically conductive surface, the waveguide member propagating the electromagnetic wave which propagates in the first throughhole, and   a plurality of second electrically conductive rods each having a leading end opposing the fourth electrically conductive surface, the plurality of second electrically conductive rods being on both sides of the waveguide member.   
     
     
         14 . An antenna device comprising:
 the waveguide device of  claim 1 ; and   at least one antenna element that is connected to a waveguide in the waveguiding wall of the waveguide device, the at least one antenna element being used for at least one of transmission and reception.   
     
     
         15 . A radar comprising:
 the antenna device of  claim 14 ; and   a microwave integrated circuit that is connected to the antenna device.