Patent ID: 8081113
Filing Date: 2011-12-20
Classification: H01Q

Abstract:
1. A microstrip antenna, comprising: (a) a first substrate with a first surface and a second surface paralleled to each other; (b) a metal ground plane with a rectangular aperture disposed on the first surface and exposing parts of the first substrate via the rectangular aperture; (c) a ring antenna having a current phase distribution; and (d) a metal feed line disposed on the second surface, wherein the metal feed line has a current phase distribution matched with the current phase distribution of the ring antenna so as to excite a relatively higher order operation mode of the ring antenna, and a first and a second intersections with the rectangular aperture on a horizontal projection plane, in order to feed a signal received or transmitted by the microstrip antenna, wherein the rectangular aperture has a longer side and a shorter side, the metal feed line has an endpoint and a current feeding point, the first intersection is arranged near the endpoint, the second intersection is arranged near to the current feeding point, and a characteristic length from the endpoint to the second intersection is ranged between wherein n is a positive integer and L is a wavelength of an applied frequency of the microstrip antenna.