Communication device
A communication device includes a wideband antenna, a reflector, and at least one metal loop. The wideband antenna is configured to cover an operation frequency band. The reflector is configured to reflect the radiation energy from the wideband antenna. The metal loop is positioned between the wideband antenna and the reflector. The distance between the wideband antenna and the reflector is shorter than 0.25 wavelength of a central frequency of the operation frequency band.
1. A communication device, comprising:
a wideband antenna, covering an operation frequency band;
a reflector, reflecting radiation energy from the wideband antenna; and
a first metal loop, disposed between the wideband antenna and the reflector;
wherein a distance between the wideband antenna and the reflector is shorter than 0.25 wavelength of a central frequency of the operation frequency band;
wherein the communication device further comprises:
a second metal loop, disposed between the wideband antenna and the reflector, wherein the second metal loop has the same shape and size as the first metal loop;
wherein a distance between the second metal loop and the first metal loop is from 0.04 to 0.2 wavelength of the central frequency of the operation frequency band.
2. The communication device as claimed in claim 1 , wherein the reflector is a metal plane.
3. The communication device as claimed in claim 1 , wherein the wideband antenna is a diamond-shaped dipole antenna.
4. The communication device as claimed in claim 1 , wherein the distance between the wideband antenna and the reflector is reduced to 0.125 wavelength of the central frequency of the operation frequency band or shorter.
5. The communication device as claimed in claim 1 , wherein a distance between the wideband antenna and the first metal loop is substantially equal to a distance between the first metal loop and the reflector.
6. The communication device as claimed in claim 1 , wherein the first metal loop substantially has a hollow rectangular shape.
7. The communication device as claimed in claim 1 , wherein a length of the first metal loop is shorter than 0.5 wavelength of the central frequency of the operation frequency band.
8. The communication device as claimed in claim 1 , wherein a length of the first metal loop is from 0.25 to 0.4 wavelength of the central frequency of the operation frequency band.
9. The communication device as claimed in claim 1 , wherein a width of the first metal loop is from 0.025 to 0.2 wavelength of the central frequency of the operation frequency band.
10. The communication device as claimed in claim 1 , further comprising:
a third metal loop, disposed between the wideband antenna and the reflector, wherein the third metal loop has the same shape and size as the first metal loop.
11. The communication device as claimed in claim 1 , wherein the operation frequency band is from 698 MHz to 894 MHz.
12. A communication device, comprising:
a wideband antenna, covering an operation frequency band;
a reflector, reflecting radiation energy from the wideband antenna;
a first metal piece, disposed between the wideband antenna and the reflector; and
a second metal piece, disposed between the wideband antenna and the reflector;
wherein a distance between the wideband antenna and the reflector is shorter than 0.25 wavelength of a central frequency of the operation frequency band;
wherein the first metal piece and the second metal piece are floating and not electrically connected to the reflector;
wherein a distance between the first metal piece and the second metal piece is from 0.04 to 0.2 wavelength of the central frequency of the operation frequency band.
13. The communication device as claimed in claim 12 , wherein the distance between the wideband antenna and the reflector is reduced to 0.125 wavelength of the central frequency of the operation frequency band or shorter.
14. The communication device as claimed in claim 12 , wherein each of the first metal piece and the second metal piece substantially has a filled rectangular shape.
15. The communication device as claimed in claim 12 , wherein a length of each of the first metal piece and the second metal piece is shorter than 0.5 wavelength of the central frequency of the operation frequency band.
16. The communication device as claimed in claim 12 , wherein a length of each of the first metal piece and the second metal piece is from 0.25 to 0.4 wavelength of the central frequency of the operation frequency band.
17. The communication device as claimed in claim 12 , wherein a width of each of the first metal piece and the second metal piece is from 0.025 to 0.2 wavelength of the central frequency of the operation frequency band.