Reader and RFID reader

Patent metadata

Field	Value
Publication number	US-9520902-B2
Application number	US-201514807179-A
Country	US
Kind code	B2
Filing date	Jul 23, 2015
Priority date	Oct 13, 2014
Publication date	Dec 13, 2016
Grant date	Dec 13, 2016

Abstract

A reader is provided, including a power amplifier (PA), a low-noise amplifier (LNA), a circulator, an auto-tuning matching network, and a control circuit. The PA emits a first RF transmission signal. The LNA transmits a first RF induced signal corresponding to the first RF transmission signal. The circulator is coupled between the PA and LNA, transmits the first RF transmission signal to an RF connection terminal or receives the first RF induced signal from the RF connection terminal. The auto-tuning matching network is coupled to the circulator, matches impedances between the circulator and the RF connection terminal. The control circuit is coupled to the auto-tuning matching network, adjusts the auto-tuning matching network to match impedances between the circulator and the RF connection terminal.

First claim

What is claimed is:

1. A reader, comprising:
a power amplifier, configured to output a first Radio Frequency (RF) transmission signal;
a low-noise amplifier, configured to transmit a first RF response signal according to the first RF transmission signal;
a circulator, coupled between the power amplifier and the low-noise amplifier, configured to transmit the first RF transmission signal to an RF connection node or receive the first RF response signal from the RF connection node;
an automatic-matching-and-tuning circuit, coupled to the circulator, configured to perform impedance matching between the RF connection node and the circulator;
a control circuit, coupled to the automatic-matching-and-tuning circuit, configured to adjust the automatic-matching-and-tuning circuit to perform impedance matching between the RF connection node and the circulator, the first RF response signal carrying an upper-tag signal and a lower-tag signal;
a mixer, coupled to the low-noise amplifier, configured to down-convert the first RF response signal; and
a selectable filter, coupled to the mixer, configured to filter the down-convert upper-tag and lower-tag signals, and select a clearer one from the filtered upper-tag and lower-tag signals to output.

2. The reader of claim 1 , further comprising:
an analog-to-digital converter, coupled to the selectable filter, configured to digitize the filtered upper-tag signal and the filtered lower-tag signal, and determine which of the digitized upper-tag signal and the digitized lower-tag signal is clearer.

3. The reader of claim 1 , wherein when the power amplifier is configured to output the first RF transmission signal, the control circuit is configured to adjust the automatic-matching-and-tuning circuit according to a self-jamming signal from the low-noise amplifier to decrease the self-jamming signal.

4. The reader of claim 1 , wherein the first RF transmission signal has the same RF frequency as the first RF response signal.

5. The reader of claim 1 , wherein the reader is an RFID reader.

6. An RFID reader, comprising:
a power amplifier, configured to output a first Radio Frequency (RF) transmission signal;
a low-noise amplifier, configured to transmit a first RF response signal according to the first RF transmission signal, wherein the first RF response signal carries an upper-tag signal and a lower-tag signal and the first RF transmission signal has the same RF frequency as the first RF response signal;
a mixer, coupled to the low-noise amplifier, configured to down-convert the first RF response signal;
a selectable filter, coupled to the mixer, configured to filter the down-convert upper-tag and lower-tag signals, and select a clearer one from the filtered upper-tag and lower-tag signals to output;
a circulator, coupled between the power amplifier and the low-noise amplifier, configured to transmit the first RF transmission signal to an RF connection node or receive the first RF response signal from the RF connection node,
an automatic-matching-and-tuning circuit, coupled to the circulator, configured to perform impedance matching between the RF connection node and the circulator; and
a control circuit, coupled to the automatic-matching-and-tuning circuit, configured to adjust the automatic-matching-and-tuning circuit to perform impedance matching between the RF connection node and the circulator.

7. The RFID reader of claim 6 , further comprising:
an analog-to-digital converter, coupled to the selectable filter, configured to digitize the filtered upper-tag signal and the filtered lower-tag signal, and determine which of the digitized upper-tag signal and the digitized lower-tag signal is clearer.

8. The RFID reader of claim 6 , wherein when the power amplifier is configured to output the first RF transmission signal, the control circuit is configured to adjust the automatic-matching-and-tuning circuit according to a self-jamming signal from the low-noise amplifier to decrease the self-jamming signal.

Assignees

• Wistron Neweb Corp

Inventors

• Chang Chung-Ping
• Liu Kun-Sung
• Liu Chia-Chang
• Chuang Chun-Hsiung

Classifications

• H04B1/0458

  Arrangements for matching and coupling between power amplifier and antenna or between amplifying stages (matching circuits in general H03H) · CPC title

• H04B1/00 Primary

  Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission · CPC title

• H04B1/18

  Input circuits, e.g. for coupling to an antenna or a transmission line (coupling networks between antennas or lines and receivers independent of the nature of the receiver H03H) · CPC title

• G06K7/10009 Primary

  sensing by radiation using wavelengths larger than 0.1 mm, e.g. radio-waves or microwaves · CPC title