Patent ID: 6788257
Filing Date: 2004-09-07
Classification: H01Q

Abstract:
A dual-frequency (planar antenna) capable of operating in a first operation band and in a second operation band, said dual-frequency planar antenna comprising:a grounding plane; a main radiating device coupled to said grounding plane, said main radiating device having a first resonance mode of said main radiating device such that said dual-frequency antenna is capable of operating in said first operation band; a feeding means provided on said grounding plane, said feeding means being coupled to said main radiating device to transfer a microwave signal to said main radiating device; a parasitic radiating device coupled to said grounding plane, said parasitic radiating device having a concave side opposite said main radiating device and a first resonance mode of said parasitic radiating device such that said dual-frequency antenna is capable of operating in said second operation band, wherein said concave side partially surrounds said main radiating device and said first resonance mode of said parasitic radiating device is excited by the coupling of energy from said main radiating device; and a medium positioned between said main radiating device, said parasitic radiating device, and said grounding plane for isolating purpose; wherein said main radiating device and said parasitic radiating device have a first size and a second size different from the first size, respectively; said first and said second operation bands are of a first operating frequency and a second operating frequency different from the first operating frequency, respectively; and said first and said second sizes are inversely related to said first and said second operating frequencies, respectively.