초록 ▼

An antenna design for a tag operating in an radio frequency identification system minimizes the influence of reflecting surfaces upon the antenna radiation pattern. The antenna advantageously provides near uniform performance when the tag is in varying proximity to different metal reflecting surface

An antenna design for a tag operating in an radio frequency identification system minimizes the influence of reflecting surfaces upon the antenna radiation pattern. The antenna advantageously provides near uniform performance when the tag is in varying proximity to different metal reflecting surfaces. The antenna operates as a quarter wave patch antenna and is constructed from a rectangular metal patch separated from a larger metallic plane. This metallic plane serves as the reference ground plane for a circuit attached to the antenna, with a direct short between the patch and the ground plane along one edge of the patch. The dimensions of the metal patch are selected such that one quarter of a wavelength of incident radiation forms a standing wave on the antenna. A careful choice of dielectric material and lateral dimensions determine the bandwidth of the antenna. The presence of the ground plane serves as a natural advantageous plane of isolation between energy radiated from the patch antenna and otherwise reflecting surfaces which may be brought into proximity with this antenna.

대표청구항 ▼

[ We claim:] [1.] A tag operating in a radio frequency identification system comprising:an antenna for receiving a signal from at least one interrogator unit, said antenna including,a first metallic plate,a larger second metallic plate connected to said first metallic plate by a metallic conductor,

[ We claim:] [1.] A tag operating in a radio frequency identification system comprising:an antenna for receiving a signal from at least one interrogator unit, said antenna including,a first metallic plate,a larger second metallic plate connected to said first metallic plate by a metallic conductor, said second metallic plate being spaced apart from and positioned parallel to said first metallic plate for providing a reference ground plane, anda substrate material is disposed between said first and second metallic plates; andtag electronic components assembled on said substrate material, said tag electronic components including,a detector/modulator for demodulating said signal,an amplifier to amplify the demodulated signal,a clock and frame recovery circuit to recover synchronization information from the amplified demodulated signal, anda processor to process the synchronization information and the amplified demodulated signal.