Partially reflective surface antenna
The present invention relates to a partially reflective surface antenna and, more particularly, to a partially reflective surface antenna including a reflective board composed of arrays of microstrip antennas, and has advantages of low side lobe and high gain. It comprises: a substrate with an upper surface having a signal transmitting notch for transmitting and receiving a high frequency signal; a reflective board for partially reflecting the high frequency signal; and a plurality of supporting elements for supporting the reflective board on the substrate. The reflective board has a second antenna array and a first antenna array surrounded by the second antenna array, wherein the first and the second antenna array are composed of a plurality of first microstrip reflective units and a plurality of second microstrip reflective units, respectively. Besides, the distance between the first microstrip reflective units is smaller than the distance between the second microstrip reflective units.
1. A partially reflective surface antenna, adapting for receiving and transmitting a high frequency signal, which comprises:
a substrate having an upper surface, wherein the upper surface has a signal transmitting notch to receive and transmit the high frequency signal;
a reflective board for partially reflecting the high frequency signal, wherein a first antenna array and a second antenna array are disposed on the surface of the reflective board, and the first antenna array is surrounded by the second antenna array; and
a plurality of supporting elements for supporting the reflective board on the upper surface of the substrate and maintaining a specific distance between the reflective board and the substrate;
wherein the first antenna array is composed of a plurality of first microstrip reflective units, the second antenna array is composed of a plurality of second microstrip reflective units; each of said first microstrip reflective units has a size equal to that of each of said second microstrip reflective units; and the distance between the first microstrip reflective units is smaller than the distance between the second microstrip reflective units.
2. The partially reflective surface antenna as claimed in claim 1 , wherein the substrate is a microwave substrate made with the FR-4 materials.
3. The partially reflective surface antenna as claimed in claim 1 , wherein the reflective board is a microwave substrate of the FR-4 materials.
4. The partially reflective surface antenna as claimed in claim 1 , wherein the shape of the first microstrip reflective units is square.
5. The partially reflective surface antenna as claimed in claim 1 , wherein the shape of the second microstrip reflective units is square.
6. The partially reflective surface antenna as claimed in claim 1 , wherein the shape of the first microstrip reflective units is a strip-like shape.
7. The partially reflective surface antenna as claimed in claim 1 , wherein the shape of the second microstrip reflective units is a strip-like shape.
8. The partially reflective surface antenna as claimed in claim 1 , wherein the supporting elements are made of an insulating material.
9. The partially reflective surface antenna as claimed in claim 1 , wherein the frequency range of the high frequency signal is between 9 GHz and 10 GHz.
10. The partially reflective surface antenna as claimed in claim 1 , wherein the reflective board is a square board.
11. The partially reflective surface antenna as claimed in claim 1 , wherein the specific distance between the reflective board and the substrate is one-half of the wavelength of the high frequency signal.
12. The partially reflective surface antenna as claimed in claim 1 , wherein the shape of the signal transmitting notch is rectangular.
13. The partially reflective surface antenna as claimed in claim 1 , wherein the signal transmitting notch is electrically connected to a coaxial cable.