RFID beam forming system
AssigneeMojix, Inc.
InventorRamin Sadr
Life of this patent
Estimating the term…
Abstract
A multi-protocol, multi-band array antenna system may be used in Radio Frequency Identification (RFID) system reader and sensory networks. The antenna array may include array elements with an integrated low noise amplifier. The system may employ digital beam forming techniques for transmission and steering of a beam to a specific sensor tag or group of tags in an cell. The receive beam forming network is optimized for detecting signals from each sensor tag. Narrow and wideband interferences may be excised by an interference nulling algorithm. Space division multiplexing may be used by the antenna system to enhance system processing capacity.
Claims34
A method for deriving information from an RFID tag, comprising:
- transmitting RFID tag interrogation signals to an RFID tag;
- digitizing the signals received by each antenna element of an array of antenna elements from the RFID tag in response to the interrogation signals;
- performing signal processing on the digitized signals to determine relative phase and weight differences between the signals received by each of the antenna elements in the array of antenna elements from the RFID tag in response to the interrogation signals;
- delaying the digitized signals received from each of the antenna elements to compensate for any accumulated delay;
- adjusting the relative phases and weights of the digitized signals to form phase aligned and amplitude weighted signals;
- combining the adjusted signals to form a weighted combination of the phase aligned and amplitude weighted digitized signals, and deriving RFID tag information from the weighted combination of the phase aligned and amplitude weighted digitized signals.
A method for deriving information from an RFID tag, comprising:
- transmitting RFID tag interrogation signals to an RFID tag;
- receiving signals from the RFID tag in response to the interrogation signals at each element of an array of antenna elements;
- selecting signals from one of the antenna elements as a reference signal;
- determining relative phase differences between the signals received by each antenna element;
- adjusting the relative phases of the signals from each of the antenna elements relative to the reference signal by:
- autocorrelating the reference signal;
- correlating each of the received signals from the other antenna elements with the reference signal;
- separately accumulating the correlation results;
- delaying the signals received from each of the antenna elements to compensate for any accumulation delay;
- and
- applying the separately accumulated correlations from each of the antenna elements to the delayed signals received by that antenna element to derotate the phases with weighted amplitudes to form a series of phase aligned and amplitude weighted received signals from each of the antenna elements;
- and
- combining the adjusted signals to form an amplitude weighted combination of phase aligned signals, for deriving RFID tag information.
Dependencies are inferred from the claim text.