Antenna, array antenna, radar apparatus, and in-vehicle system

1. An antenna comprising:

a radiation unit that is formed on a substrate;

a waveguide that propagates therein radio waves radiated from the radiation unit and radiates the radio waves as a beam; and

a dielectric lens that is arranged in an opening of the waveguide and has an incident plane facing the radiation unit and a radiation plane radiating radio waves entered from the incident plane,

wherein the radiation plane of the dielectric lens has a plane orientation different from a flat plane perpendicular to the radiation direction of the beam,

wherein the radiation plane of the dielectric lens has a flat inclined surface having a predetermined angle with respect to a flat plane perpendicular to the radiation direction of the beam at a predetermined position nearer to the radiation direction side of the beam than an opening plane of the waveguide.

2. The antenna according to claim 1 ,

wherein the radiation unit has a first radiation unit and a second radiation unit,

wherein the waveguide has a first waveguide that propagates therein radio waves radiated from the first radiation unit and radiates the radio waves as a beam and a second waveguide that propagates therein radio waves radiated from the second radiation unit and radiates the radio waves as a beam,

wherein the dielectric lens has a first dielectric lens that is arranged in an opening of the first waveguide and has an incident plane facing the first radiation unit and a first radiation plane radiating radio waves entered from the incident plane, and a second dielectric lens that is arranged in an opening of the second waveguide and has an incident plane facing the second radiation unit and a second radiation plane radiating radio waves entered from the incident plane,

wherein the radiation plane of the first dielectric lens has a flat plane parallel to an opening plane of the first waveguide at the opening plane, and

wherein the radiation plane of the second dielectric lens has an inclined plane having a predetermined angle with respect to a flat plane perpendicular to the radiation direction of the beam at a predetermined position nearer to the radiation direction side of the beam than an opening plane of the second waveguide.

3. The antenna according to claim 1 ,

wherein the radiation unit has a first radiation unit, a second radiation unit, and a third radiation unit,

wherein the waveguide has a first waveguide that propagates therein radio waves radiated from the first radiation unit and radiates the radio waves as a beam, a second waveguide that propagates therein radio waves radiated from the second radiation unit and radiates the radio waves as a beam, and a third waveguide that propagates therein radio waves radiated from the third radiation unit and radiates the radio waves as a beam,

wherein the dielectric lens has a first dielectric lens that is arranged in an opening of the first waveguide and has an incident plane facing the first radiation unit and a first radiation plane radiating radio waves entered from the incident plane, a second dielectric lens that is arranged in an opening of the second waveguide and has an incident plane facing the second radiation unit and a second radiation plane radiating radio waves entered from the incident plane, and a third dielectric lens that is arranged in an opening of the third waveguide and has an incident plane facing the third radiation unit and a third radiation plane radiating radio waves entered from the incident plane,

wherein the radiation plane of the first dielectric lens has a flat plane parallel to an opening plane of the first waveguide at the opening plane,

wherein the radiation plane of the second dielectric lens has an inclined plane having a predetermined angle with respect to a flat plane perpendicular to the radiation direction of the beam at a predetermined position nearer to the radiation direction side of the beam than an opening plane of the second waveguide, and

wherein the radiation plane of the third dielectric lens has an inclined plane having a predetermined angle with respect to a flat plane perpendicular to the radiation direction of the beam at a predetermined position nearer to the radiation direction side of the beam than an opening plane of the third waveguide, and the inclined plane has a plane orientation different from the radiation plane of the second dielectric lens.

4. The antenna according to claim 1 ,

wherein a plurality of radiation units is formed on the substrate,

wherein the waveguide propagates therein radio waves radiated from each of the plurality of radiation units and radiates the radio waves as a beam,

wherein the dielectric lens is arranged in an opening of the waveguide and has a plurality of incident planes facing the plurality of radiation units and a radiation plane radiating radio waves entered from the incident plane,

wherein the waveguide includes a projection part formed in a tapered shape between the plurality of radiation units,

wherein a tip end of the projection part is formed nearer to the radiation side of the beam than the opening plane of the waveguide, and

wherein the radiation plane of the dielectric lens has a plane orientation different from a flat plane perpendicular to the radiation direction of the beam.

5. The antenna according to claim 1 ,

wherein a cross section of the waveguide is monotonically enlarged from the radiation unit towards the opening, and

wherein the waveguide is brought into contact with the dielectric lens in the opening opposite to the radiation unit.

6. The antenna according to claim 1 ,

wherein the shape of a cross section of the waveguide perpendicular to the radiation direction of the beam is formed to radiate a beam whose second direction is narrower than a first direction orthogonal to the second direction, and

wherein the incident plane facing the radiation unit is configured in a convex plane shape towards the radiation unit.

7. The antenna according to claim 1 ,

wherein the radiation plane of the dielectric lens is formed using a predetermined curved plane.

8. An array antenna having the plurality of antennas described in claim 1 ,

wherein the opening planes of the waveguides are arranged on the same flat plane.

9. A radar apparatus having the antenna described in claim 1 ,

wherein at least one of a transmission circuit and a reception circuit is provided, and

wherein each of the transmission circuit and the reception circuit is connected to the radiation unit.

10. An in-vehicle system having the antenna described in claim 1 ,

wherein at least one of a transmission circuit and a reception circuit is provided,

wherein each of the transmission circuit and the reception circuit is connected to the radiation unit, and

wherein a signal processing unit connected to the transmission circuit and the reception circuit and a vehicle control unit connected to the signal processing unit are provided.