Patent ID: 6295028
Filing Date: 2001-09-25
Classification: H01Q

Abstract:
A dual band antenna, comprising:at least one first antenna element and a corresponding second antenna element for forming at least one combined antenna element and transmitting and/or receiving radio frequency radiation in a first, relatively low frequency band and a second, relative high frequency band, respectively,an electrically conductive, substantially planar reflector device having a front side,said at least one first antenna element being located close to said corresponding second antenna element so as to form said at least one combined antenna element on said front side of said planar reflector device and to define first and second radiation beams, respectively, each having a specific azimuth radiation beam width being substantially symmetrical with respect to a central, longitudinal plane oriented perpendicularly to said planar reflector device and extending through said at least one combined antenna element,said planar reflector device, on each lateral side of said central, longitudinal plane, is provided with an edge portion formed as a groove, which is open towards said front side of said reflector device, said groove being dimensioned so as to widen the azimuth radiation beam width of said second radiation beam, and said grooves having a depth and a width, the depth of said groove being 0.1 to 0.3 times the wavelength of the radiation in said second, relatively high frequency band and the width of said groove being 0.1 to 0.3 times the wavelength of the radiation in said second, relatively high frequency band; andwherein the azimuth radiation beam width of said second beam is widened to an angular value being close to that of said first radiation beam, whereby both radiation beams will nearly match and have substantially the same radiation azimuth beam width.