Slot array antenna

Abstract

A slot array antenna includes: a first electrically conductive member having a first electrically conductive surface; a second electrically conductive member having a second electrically conductive surface opposed to the first electrically conductive surface; a waveguide member located between the first and second electrically conductive members; and an artificial magnetic conductor extending on both sides of the waveguide member in between the first and second electrically conductive members. The first or second electrically conductive member has a plurality of slots. The waveguide member includes an electrically-conductive waveguide face of a stripe shape opposed to the first electrically conductive surface. The plurality of slots include at least two slots that couple to the waveguide face. In between two positions respectively coupled to the two slots, the waveguide face includes at least one deflecting portion at which the direction that the waveguide face extends changes.

What is claimed is: 
     
         1 . A slot array antenna to be connected to a transmitter or a receiver in use, comprising:
 a first conductive member having a first electrically conductive surface;   a second electrically conductive member having a second electrically conductive surface opposed to the first electrically conductive surface;   a waveguide member located between the first electrically conductive member and the second electrically conductive member and extending alongside the first electrically conductive surface, the waveguide member having a stripe-shaped electrically-conductive waveguide face opposed to the first electrically conductive surface;   another waveguide member located between the first electrically conductive member and the second electrically conductive member and extending alongside the first electrically conductive surface, the other waveguide member having a stripe-shaped electrically-conductive another waveguide face opposed to the first electrically conductive surface; and   an artificial magnetic conductor extending on both sides of the waveguide member in between the first electrically conductive member and the second electrically conductive member, and on both sides of the other waveguide member in between the first electrically conductive member and the second electrically conductive member; wherein,   a waveguide is defined by the waveguide face, the first electrically conductive surface and the artificial magnetic conductor;   another waveguide is defined by the other waveguide face, the first electrically conductive surface and the artificial magnetic conductor;   at least one of the first electrically conductive member and the second electrically conductive member has a set of slots arranged along the first electrically conductive surface or the second electrically conductive surface;   at least one of the first electrically conductive member and the second electrically conductive member has another set of slots arranged along the first electrically conductive surface or the second electrically conductive surface;   the set of slots include a first slot and a second slot which are adjacent to each other and each of which couples to the waveguide;   the other set of slots include another first slot and another second slot which are adjacent to each other and each of which couples to the other waveguide;   in between two positions respectively coupled to the first slot and the second slot, the waveguide includes at least one first deflecting portion at which a direction that the waveguide extends changes;   in between two another positions respectively coupled to the other first slot and the other second slot, the other waveguide includes at least one other first deflecting portion at which a direction that the other waveguide extends changes;   a line segment connecting between centers of the first slot and the second slot, and another line segment connecting between centers of the other first slot and the other second slot, are substantially parallel;   shifting the line segment in a direction which is orthogonal to a direction that the line segment extends allows at least a portion of the line segment to overlap the other line segment; and   a direction of deflection of the first deflecting portion is identical to a direction of deflection of the other first deflecting portion.   
     
     
         2 . The slot array antenna of  claim 1 , wherein
 at least the waveguide face has two edges that together define width of the waveguide face;   each of the first slot and the second slot has an opening that extends through the first electrically conductive member and is open on the first electrically conductive surface; and   as viewed from a normal direction of the first electrically conductive surface, a central portion of the opening along a length direction thereof overlaps the second electrically conductive surface on an outside of one of the two edges of the waveguide face.   
     
     
         3 . The slot array antenna of  claim 1 , wherein,
 the set of slots include a third slot which is adjacent to the second slot;   the waveguide includes, in between two positions respectively coupled to the second slot and the third slot, at least one second deflecting portion at which the direction that the waveguide extends changes;   a direction of deflection of the first deflecting portion and a direction of deflection of the second deflecting portion are opposite;   the other set of slots include another third slot which is adjacent to the other second slot;   the other waveguide includes, in between two positions respectively coupled to the other second slot and the other third slot, at least one other second deflecting portion at which the direction that the other waveguide extends changes; and   a direction of deflection of the other first deflecting portion and a direction of deflection of the other second deflecting portion are opposite.   
     
     
         4 . The slot array antenna of  claim 1 , wherein,
 the artificial magnetic conductor includes a plurality of electrically conductive rods each having a leading end opposing the first electrically conductive surface;   the plurality of electrically conductive rods include one or more rows of the electrically conductive rods that are adjacent to and arrayed along the waveguide member;   at a position adjacent to the deflecting portion, a row of the electrically conductive rods deflects in accordance with a direction of deflection of the deflecting portion; and   at least one of the plurality of electrically conductive rods is disposed between the first slot and the second slot.   
     
     
         5 . The slot array antenna of  claim 1 , wherein
 the plurality of electrically conductive rods include one or more rows of the electrically conductive rods that are adjacent to and arrayed along the waveguide member;   the one or more rows of electrically conductive rods include an outer rod row arrayed on an outside of the deflecting portion and an inner rod row arrayed on an inside of the deflecting portion; and,   between a plane which passes through a center of the first slot and which contains a width direction of the waveguide face and a plane which passes through a center of the second slot and which contains the width direction of the waveguide face, there are more electrically conductive rods included in the outer rod row than there are electrically conductive rods included in the inner rod row.   
     
     
         6 . A radar system comprising:
 the slot array antenna of  claim 1 ;   at least one of a transmitter and a receiver that is connected to the slot array antenna;   at least one of a D/A converter that is connected to the transmitter and an A/D converter that is connected to the receiver; and   a signal processing circuit that is connected to the at least one of the D/A converter and the A/D converter, wherein,   the at least one of the transmitter and the receiver comprises a microwave integrated circuit; and   the signal processing circuit performs at least one of direction-of-arrival estimation and distance estimation.   
     
     
         7 . A communication system comprising:
 the slot array antenna of  claim 1 ;   at least one of a transmitter and a receiver that is connected to the slot array antenna;   at least one of a D/A converter that is connected to the transmitter and an A/D converter that is connected to the receiver; and   a signal processing circuit that is connected to the at least one of the D/A converter and the A/D converter, wherein   the signal processing circuit performs at least one of encoding of a digital signal and decoding of a digital signal.   
     
     
         8 . A slot array antenna to be connected to a transmitter or a receiver in use, comprising:
 a first conductive member having a first electrically conductive surface;   a second electrically conductive member having a second electrically conductive surface opposed to the first electrically conductive surface;   a waveguide member located between the first electrically conductive member and the second electrically conductive member and extending alongside the first electrically conductive surface, the waveguide member having a stripe-shaped electrically-conductive waveguide face opposed to the first electrically conductive surface;   another waveguide member located between the first electrically conductive member and the second electrically conductive member and extending alongside the first electrically conductive surface, the other waveguide member having a stripe-shaped electrically-conductive another waveguide face opposed to the first electrically conductive surface; and   an artificial magnetic conductor extending on both sides of the waveguide member in between the first electrically conductive member and the second electrically conductive member, and on both sides of the other waveguide member in between the first electrically conductive member and the second electrically conductive member; wherein,   a waveguide is defined by the waveguide face, the first electrically conductive surface and the artificial magnetic conductor;   another waveguide is defined by the other waveguide face, the first electrically conductive surface and the artificial magnetic conductor;   at least one of the first electrically conductive member and the second electrically conductive member has a set of slots arranged along the first electrically conductive surface or the second electrically conductive surface;   at least one of the first electrically conductive member and the second electrically conductive member has another set of slots arranged along the first electrically conductive surface or the second electrically conductive surface;   the set of slots include a first slot and a second slot which are adjacent to each other and each of which couples to the waveguide;   the other set of slots include another first slot and another second slot which are adjacent to each other and each of which couples to the other waveguide;   in between two positions respectively coupled to the first slot and the second slot, the waveguide includes at least one first deflecting portion at which a direction that the waveguide extends changes;   in between two another positions respectively coupled to the other first slot and the other second slot, the other waveguide includes at least one other first deflecting portion at which a direction that the other waveguide extends changes;   lines interconnecting respective centers of the first slot, the second slot, the other first slot and the other second slot present a convex quadrilateral; and   a direction of deflection of the first deflecting portion is identical to a direction of deflection of the other first deflecting portion.   
     
     
         9 . The slot array antenna of  claim 8 , wherein
 at least the waveguide face has two edges that together define width of the waveguide face;   each of the first slot and the second slot has an opening that extends through the first electrically conductive member and is open on the first electrically conductive surface; and   as viewed from a normal direction of the first electrically conductive surface, a central portion of the opening along a length direction thereof overlaps the second electrically conductive surface on an outside of one of the two edges of the waveguide face.   
     
     
         10 . The slot array antenna of  claim 8 , wherein,
 the set of slots include a third slot which is adjacent to the second slot;   the waveguide includes, in between two positions respectively coupled to the second slot and the third slot, at least one second deflecting portion at which the direction that the waveguide extends changes;   a direction of deflection of the first deflecting portion and a direction of deflection of the second deflecting portion are opposite;   the other set of slots include another third slot which is adjacent to the other second slot;   the other waveguide includes, in between two positions respectively coupled to the other second slot and the other third slot, at least one other second deflecting portion at which the direction that the other waveguide extends changes; and   a direction of deflection of the other first deflecting portion and a direction of deflection of the other second deflecting portion are opposite.   
     
     
         11 . The slot array antenna of  claim 8 , wherein,
 the artificial magnetic conductor includes a plurality of electrically conductive rods each having a leading end opposing the first electrically conductive surface;   the plurality of electrically conductive rods include one or more rows of the electrically conductive rods that are adjacent to and arrayed along the waveguide member;   at a position adjacent to the first deflecting portion, a row of the electrically conductive rods deflects in accordance with a direction of deflection of the first deflecting portion; and   at least one of the plurality of electrically conductive rods is disposed between the first slot and the second slot.   
     
     
         12 . The slot array antenna of  claim 11 , wherein
 the plurality of electrically conductive rods include one or more rows of the electrically conductive rods that are adjacent to and arrayed along the waveguide member;   the one or more rows of electrically conductive rods include an outer rod row arrayed on an outside of the first deflecting portion and an inner rod row arrayed on an inside of the first deflecting portion; and,   between a plane which passes through a center of the first slot and which contains a width direction of the waveguide face and a plane which passes through a center of the second slot and which contains the width direction of the waveguide face, there are more electrically conductive rods included in the outer rod row than there are electrically conductive rods included in the inner rod row.   
     
     
         13 . A radar system comprising:
 the slot array antenna of  claim 8 ;   at least one of a transmitter and a receiver that is connected to the slot array antenna;   at least one of a D/A converter that is connected to the transmitter and an A/D converter that is connected to the receiver; and   a signal processing circuit that is connected to the at least one of the D/A converter and the A/D converter, wherein,   the at least one of the transmitter and the receiver comprises a microwave integrated circuit; and   the signal processing circuit performs at least one of direction-of-arrival estimation and distance estimation.   
     
     
         14 . A communication system comprising:
 the slot array antenna of  claim 8 ;   at least one of a transmitter and a receiver that is connected to the slot array antenna;   at least one of a D/A converter that is connected to the transmitter and an A/D converter that is connected to the receiver; and   a signal processing circuit that is connected to the at least one of the D/A converter and the A/D converter, wherein   the signal processing circuit performs at least one of encoding of a digital signal and decoding of a digital signal.   
     
     
         15 . A slot array antenna to be connected to a transmitter or a receiver in use, comprising:
 a first conductive member having a first electrically conductive surface;   a second electrically conductive member having a second electrically conductive surface opposed to the first electrically conductive surface;   a waveguide member located between the first electrically conductive member and the second electrically conductive member and extending alongside the first electrically conductive surface, the waveguide member having a stripe-shaped electrically-conductive waveguide face opposed to the first electrically conductive surface; and   an artificial magnetic conductor extending on both sides of the waveguide member in between the first electrically conductive member and the second electrically conductive member, wherein,   a waveguide is defined by the waveguide face, the first electrically conductive surface and the artificial magnetic conductor;   at least one of the first electrically conductive member and the second electrically conductive member has a plurality of slots arranged along the first electrically conductive surface or the second electrically conductive surface;   the plurality of slots include two slots which are adjacent to each other and each of which couples to the waveguide;   in between two positions respectively coupled to the two slots, the waveguide includes at least one deflecting portion at which a direction that the waveguide extends changes;   as viewed from a normal direction of the waveguide face, the waveguide face includes an extension that extends beyond at least one of the two slots and away from the deflecting portion;   a distance between the two positions as measured along the waveguide face is greater than half a length of at least one of the two slots;   a straight distance between centers of the two slots is smaller than four times the length of either of the two slots; and   the transmitter or the receiver couples to the waveguide face at the extension side.   
     
     
         16 . The slot array antenna of  claim 15 , wherein
 the waveguide face has two edges that together define width of the waveguide face;   each of the two slots has an opening that extends through the first electrically conductive member and is open on the first electrically conductive surface; and   as viewed from a normal direction of the first electrically conductive surface, a central portion of the opening along a length direction thereof overlaps the second electrically conductive surface on an outside of one of the two edges of the waveguide face.   
     
     
         17 . The slot array antenna of  claim 15 , wherein,
 the plurality of slots include a third slot which is adjacent to the second slot;   the waveguide includes, in between two positions respectively coupled to the second slot and the third slot, at least one other deflecting portion at which the direction that the waveguide extends changes; and   a direction of deflection of the deflecting portion and a direction of deflection of the other deflecting portion are opposite.   
     
     
         18 . The slot array antenna of  claim 15 , wherein,
 the artificial magnetic conductor includes a plurality of electrically conductive rods each having a leading end opposing the first electrically conductive surface;   the plurality of electrically conductive rods include one or more rows of the electrically conductive rods that are adjacent to and arrayed along the waveguide member;   at a position adjacent to the deflecting portion, a row of the electrically conductive rods deflects in accordance with a direction of deflection of the deflecting portion; and   at least one of the plurality of electrically conductive rods is disposed between the two slots.   
     
     
         19 . The slot array antenna of  claim 18 , wherein
 the one or more rows of electrically conductive rods include an outer rod row arrayed on an outside of the deflecting portion and an inner rod row arrayed on an inside of the deflecting portion; and,   between a plane which passes through a center of the first slot and which contains a width direction of the waveguide face and a plane which passes through a center of the second slot and which contains the width direction of the waveguide face, there are more electrically conductive rods included in the outer rod row than there are electrically conductive rods included in the inner rod row.   
     
     
         20 . The slot array antenna of  claim 15 , wherein, in the deflecting portion, an outer edge of the waveguide member is chamfered or rounded. 
     
     
         21 . A radar system comprising:
 the slot array antenna of  claim 18 ;   at least one of a transmitter and a receiver that is connected to the slot array antenna;   at least one of a D/A converter that is connected to the transmitter and an A/D converter that is connected to the receiver; and   a signal processing circuit that is connected to the at least one of the D/A converter and the A/D converter, wherein,   the at least one of the transmitter and the receiver comprises a microwave integrated circuit; and   the signal processing circuit performs at least one of direction-of-arrival estimation and distance estimation.   
     
     
         22 . A communication system comprising:
 the slot array antenna of  claim 18 ;   at least one of a transmitter and a receiver that is connected to the slot array antenna;   at least one of a D/A converter that is connected to the transmitter and an A/D converter that is connected to the receiver; and   a signal processing circuit that is connected to the at least one of the D/A converter and the A/D converter, wherein   the signal processing circuit performs at least one of encoding of a digital signal and decoding of a digital signal.