Antenna assembly and method for manufacturing the same
In an antenna apparatus, at least one choke in the form of a groove is arranged between a transmitting antenna and a receiving antenna. The choke functions to suppress the mutual electromagnetic coupling between the transmitting antenna and the receiving antenna. The depth of the choke is in a range from 0.15, to less than 0.225λ where λ is a wavelength of a carrier wave.
1. An antenna apparatus that operates in millimeter waveband or microwave band, the antenna apparatus comprising:
a ground conductor;
a transmitting antenna arranged on the ground conductor and connected to a first feed line;
a receiving antenna arranged on the ground conductor and connected to a second feed line; and
one or more chokes that are arranged on the ground conductor between the transmitting antenna and the receiving antenna, and are operative to suppress an electromagnetic coupling between the transmitting antenna and the receiving antenna, wherein is all of the one or more chokes are in a form of a groove which has a bottom surface at a depth below an opening in the ground conductor, and the depth of the bottom surface is in a range from 0.15λ to less than 0.225λ, where λ is a wavelength of a carrier wave of the transmitting antenna.
2. The antenna apparatus according to claim 1 , wherein the one or more chokes are a plurality of chokes which are arranged in plurality and parallel to each other.
3. The antenna apparatus according to claim 2 , wherein a distance between adjoining chokes is about 0.25λ.
4. The antenna apparatus according to claim 3 , further comprising:
a first metal plate that forms a top layer of the ground conductor and on which a transmitting antenna aperture, a receiving antenna aperture, and a choke slit are arranged; and
a second metal plate that is bound with the first metal plate by a method of diffusion bonding and through which the transmitting antenna aperture and the receiving antenna aperture pass.
5. The antenna apparatus according to claim 2 , wherein the depth of the bottom surface is in a range from 0.15λ to 0.2λ.
6. The antenna apparatus according to claim 5 , further comprising:
a first metal plate that forms a top layer of the ground conductor and on which a transmitting antenna aperture, a receiving antenna aperture, and a choke slit are arranged; and
a second metal plate that is bound with the first metal plate by a method of diffusion bonding and through which the transmitting antenna aperture and the receiving antenna aperture pass.
7. The antenna apparatus according to claim 2 , further comprising:
a first metal plate that forms a top layer of the ground conductor and on which a transmitting antenna aperture, a receiving antenna aperture, and a choke slit are arranged; and
a second metal plate that is bound with the first metal plate by a method of diffusion bonding and through which the transmitting antenna aperture and the receiving antenna aperture pass.
8. The antenna apparatus according to claim 1 , further comprising:
a first metal plate that forms a top layer of the ground conductor and on which a transmitting antenna aperture, a receiving antenna aperture, and a choke slit are arranged; and
a second metal plate that is bound with the first metal plate by a method of diffusion bonding and through which the transmitting antenna aperture and the receiving antenna aperture pass.
9. The antenna apparatus according to claim 1 , wherein there exists only a single choke between the transmitting antenna and the receiving antenna.
10. The antenna apparatus according to claim 9 , wherein the single choke is located at a central point between the transmitting antenna and the receiving antenna.
11. The antenna apparatus according to claim 1 , wherein a distance from the receiving antenna to the transmitting antenna is an integral multiple of λ.
12. The antenna apparatus according to claim 1 , wherein the transmitting antenna extends in a first direction, the receiving antenna extends in the first direction parallel to the transmitting antenna, and the one or more chokes extend in the first direction parallel to the transmitting and receiving antennas so as to extend beyond the transmitting and receiving antennas in the first direction.
13. The antenna apparatus according to claim 1 , wherein the groove has a width in a range from 0.15λ to 0.3λ.
14. A method of manufacturing an antenna apparatus that operates in millimeter waveband or microwave band, the method comprising:
manufacturing a first metal plate that has a thickness in a range from 0.15λ to less than 0.225λ wherein λ is a wavelength of a carrier wave, and includes a ground conductor, and on which a transmitting antenna aperture, a receiving antenna aperture, and one or more choke grooves with a bottom surface below an opening in the ground conductor and all of the one or more chokes having a depth corresponding to the thickness of the first metal plate are arranged;
manufacturing a second metal plate through which the transmitting antenna aperture and the receiving antenna aperture pass; and applying diffusion bonding to the first metal plate and the second metal plate by matching a corresponding position of the transmitting antenna and the receiving antenna aperture.