Back to results
US 7,612,719 B2Granted
RFID near field linear antenna
AssigneeSensormatic Electronics Corporation
InventorsRichard L. Copeland, Gary Mark Shafer
Life of this patent
Estimating the term…
Abstract
A near field linear element microstrip antenna is disclosed which is configured to read an RFID label such that a localized electric E field emitted by the antenna at an operating wavelength resides substantially within a zone defined by the near field. The localized E field directs a current distribution along an effective length of the antenna corresponding to a half-wave to a full-wave structure.
Claims18
A near field RFID antenna assembly comprising a substantially linear element microstrip antenna comprising:
- a substrate having a thickness H;
- a feed point at an end region of the substantially linear element microstrip antenna;
- a terminating resistor at an end region of the substantially linear element microstrip antenna opposite the feed point;
- a linear microstrip line, the linear microstrip line electrically connecting the feed point and the terminating resistor, the linear micro strip line having a width W;
- the antenna configured such that:
- a localized electric E field emitted by the antenna resides substantially within a zone defined by the near field;
- the localized electric E field directs a current distribution along a length of the antenna corresponding to a half wave to a full-wave structure;
- an input impedance Z in ohms at the feed point is substantially equal to the impedance of the terminating resistor;
- and
- a ratio of W/H ranges from about 1 to about 5.
7 more elements
Dependencies are inferred from the claim text.