The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.

The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.

Date of Patent:
May. 03, 2011

Filed:

Dec. 27, 2007
Applicants:

Hee-chan Choi, Suwon-si, KR;

Seung-bum Kim, Suwon-si, KR;

Dong-woo Lee, Suwon-si, KR;

Inventors:

Hee-Chan Choi, Suwon-si, KR;

Seung-Bum Kim, Suwon-si, KR;

Dong-Woo Lee, Suwon-si, KR;

Attorney:
Primary Examiner:
Int. Cl.
CPC ...
H04B 1/38 (2006.01);
U.S. Cl.
CPC ...
Abstract

Disclosed is an apparatus and a method for improving the receive (Rx) sensitivity of a portable Radio Frequency IDentification (RFID). The portable RFID reader/writer is equipped with a variable phase shifter which is connected between an antenna and a directional coupler and then changes an impedance in the direction of the antenna in response to controlling a phase shift, a level of a reflection signal if a transmit (Tx) signal of the portable RFID reader/writer reflected by the antenna flows into an Rx path is measured, and then the phase shift of the variable phase shifter is controlled in such a manner as to minimize the measured level of the reflection signal. Therefore, calibration is implemented so that an antenna impedance changing in response to a position in which contact is made by a user's hand may have an adaptively optimal antenna reflection coefficient, thereby improving the Rx sensitivity.


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