Patent ID: 7295162

Claim:
A dual-frequency directional antenna, comprising: a dielectric substrate, having a front surface and a rear surface; two first low frequency antenna elements, disposed on said front surface of said dielectric substrate; a first symmetrical micro-strip line, disposed on said front surface of said dielectric substrate, the two ends of said first symmetrical micro-strip line being respectively connected with said first low frequency antenna elements; two first high frequency antenna elements, disposed on said front surface of said dielectric substrate and between said two first low frequency antenna elements, said two first high frequency antenna elements being connected with said first symmetrical micro-strip line; a first balun, disposed on said front surface of said dielectric substrate and between said two first high frequency antenna elements, one end of said first balun being connected to a middle segment of said first symmetrical micro-strip line and the other end of said first balun being connected to an antenna feeding port, wherein said first balun and said first high frequency antenna elements are disposed at one side of said first symmetrical micro-strip line, and said first low frequency antenna elements are disposed at the other side of said first symmetrical micro-strip line; two second low frequency antenna elements, disposed on said rear surface of said dielectric substrate; a second symmetrical micro-strip line, disposed on said rear surface of said dielectric substrate, the two ends of said second symmetrical micro-strip line being respectively connected with said second low frequency antenna elements; two second high frequency antenna elements, disposed on said rear surface of said dielectric substrate and between said two second low frequency antenna elements, said two second high frequency antenna elements being connected with said second symmetrical micro-strip line; and a second balun, disposed on said rear surface of said dielectric substrate and between said two second high frequency antenna elements, one end of said second balun being connected to a middle segment of said second symmetrical micro-strip line and the other end of said second balun being connected to an antenna feeding port, wherein said second balun and said second low frequency antenna elements are disposed at one side of said second symmetrical micro-strip line, and said second high frequency antenna elements are disposed at the other side of said second symmetrical micro-strip line.