Abstract: The invention describes an arbitration management method and system for use in identifying RFID transponders or tags which each transmit a response signal to a reader within a respective waiting period the maximum duration of which can be adjusted. The maximum duration is determined by a random number transmitted to a counter along a number of data lines, at least one of the data lines being provided with logic gates which block or permit data line signals reaching the binary inputs of the counter to control the maximum length of the waiting period.

Abstract: A RFID tag or label comprises a RFID tag module (comprising an electronic identification circuit and a coupling means) and an antenna structure coupled to the coupling means. The RFID tag module is separate from, separable or arranged to be severable from, the antenna structure. The tag module can be placed in or on an object and the antenna structure in or on packaging material for use with the object. A patch antenna type RFID tag antenna structure has a ground plane spaced from the patch antenna so as to increase the range of the tag. The ground plane is not substantially larger than, and electrically insulated from, the patch antenna. The ground plane is flexible, so the RFID tag structure can be worn by a human, and can be incorporated into a piece of clothing. A RFID antenna structure for use with a tag reader is made flat and robust so that it can be mounted on the ground to be walked upon or driven over.

Abstract: An electronic radio frequency (RF) identification system 10 is disclosed and claimed. The system includes an interrogator 11 and a plurality of RF transponders 12.1 to 12.n. In use, each transponder is operative in response to an interrogation signal 14 to respond with a forward error correctable data message 16.1 including base data encoded as symbol characters in accordance with a forward error correcting code, such as a Reed Solomon Code, and check characters on the base data as defined in the forward error correcting code. The interrogator 11 utilizes data relating to the forward error correcting code, the symbol characters and check characters in the received forward error correctable data message, to reconstruct the base data in the event of corruption of the forward error correctable data message during transmission.

Abstract: An RF electronic identification system (10) is disclosed and claimed. The system includes at least one transponder encoder (14.1) for writing data into a memory arrangement (52) of a selected transponder (1.1) of a plurality of transponders (1.1 to 1.n) adapted to receive data from the at least one encoder. The system further includes at least one verifier (16) for interrogating a selected transponder (1.1) and to read data stored in the transponder. The encoder includes a controller (42) for providing an identification code characteristic of the encoder to form part of the data to be written into the transponder. The verifier includes computing means (56) for extracting the identification code from the data read thereby and for comparing the code to authorized codes. An indicator (18) provides an indication whether the identification code corresponds to any of the authorized codes or not. A method of verifying the authenticity of a transponder is also disclosed and claimed.

Abstract: A method of reading a plurality of transponders 14.1 to 14.n forming part of an electronic radio frequency identification system 10 comprises the steps of prompting the transponders at 38 to transmit preambles 30 only of respective response digital sequences to a reader 12. The reader then locks onto the preamble 30 transmitted by one of the transponders and immediately causes a mute signal 38 to be broadcast to mute all of the transponders not yet transmitting. The reader then transmits during a first time window 42 a first command 40 to cause the one transponder to transmit a remainder of the sequence. Having received and read the remainder, the reader transmits a second command 44 during a second time window 46 to cause the one transponder to switch to a sleep mode wherein the one transponder no longer transmits any part of the sequence, and to unmute the muted transponders.

Abstract: A method of reading a plurality of transponders 14.1 to 14.n forming part of an electronic radio frequency identification system 10 comprises the steps of prompting the transponders at 38 to transmit preambles 30 only of respective response digital sequences to a reader 12. The reader then locks onto the preamble 30 transmitted by one of the transponders and immediately causes a mute signal 38 to be broadcast to mute all of the transponders not yet transmitting. The reader then transmits during a first time window 42 a first command 40 to cause the one transponder to transmit a remainder of the sequence. Having received and read the remainder, the reader transmits a second command 44 during a second time window 46 to cause the one transponder to switch to a sleep mode wherein the one transponder no longer transmits any part of the sequence, and to unmute the muted transponders.

Abstract: An electronic radio frequency (RF) identification system 10 is disclosed and claimed. The system includes an interrogator 11 and a plurality of RF transponders 12.1 to 12.n. In use, each transponder is operative in response to an interrogation signal 14 to respond with a forward error correctable data message 16.1 including base data encoded as symbol characters in accordance with a forward error correcting code, such as a Reed Solomon Code, and check characters on the base data as defined in the forward error correcting code. The interrogator 11 utilizes data relating to the forward error correcting code, the symbol characters and check characters in the received forward error correctable data message, to reconstruct the base data in the event of corruption of the forward error correctable data message during transmission.

Abstract: An RF electronic identification system (10) is disclosed and claimed. The system includes at least one transponder encoder (14.1) for writing data into a memory arrangement (52) of a selected transponder (1.1) of a plurality of transponders (1.1 to 1.n) adapted to receive data from the at least one encoder. The system further includes at least one verifier (16) for interrogating a selected transponder (1.1) and to read data stored in the transponder. The encoder includes a controller (42) for providing an identification code characteristic of the encoder to form part of the data to be written into the transponder. The verifier includes computing means (56) for extracting the identification code from the data read thereby and for comparing the code to authorized codes. An indicator (18) provides an indication whether the identification code corresponds to any of the authorized codes or not. A method of verifying the authenticity of a transponder is also disclosed and claimed.

Abstract: A transponder 14.1 for an electronic radio frequency identification system comprises an antenna 18 having an antenna impedance at a feedpoint thereof. The transponder further comprises an electronic circuit 19 having an input connected to the antenna. The antenna impedance having impedance characteristics for developing first and second voltage maxima (36, 38) across the input at first and second frequencies (fL and fH) respectively, thereby to provide a continuous operative frequency band for the transponder including the first and second frequencies.

Abstract: A transponder 14.1 for a radio frequency (RF) identification system comprises an antenna 22.1 having an antenna impedance (ZA) having a real part (RA) connected to transponder circuitry presenting a load impedance (ZL) having a real part (RL), a ratio ( R L R A ) of the real part (RL) of the load impedance and the real part (RA) of the antenna impedance having a first value that is bigger than one when the transponder is not transmitting data. During transmission of data the ratio is switched between the first value and a second smaller value.

Abstract: An electronic radio frequency identification system comprises a reader 12 and a plurality of transponders to be read by the reader. The reader comprises a recovery circuit 32 for recovering and separating an upper sideband 26.12 and a lower sideband 26.11 of a modulated response signal 26.1 from one of the transponders. The reader further comprises an evaluating circuit 38 for evaluating and selecting one of the upper sideband the lower sideband for output to a next stage, based on the evaluation.

Abstract: An RF electronic identification system (10) is disclosed and claimed. The system includes at least one transponder encoder (14.1) for writing data into a memory arrangement (52) of a selected transponder (1.1) of a plurality of transponders (1.1 to 1.n) adapted to receive data from the at least one encoder. The system further includes at least one verifier (16) for interrogating a selected transponder (1.1) and to read data stored in the transponder. The encoder includes a controller (42) for providing an identification code characteristic of the encoder to form part of the data to be written into the transponder. The verifier includes computing means (56) for extracting the identification code from the data read thereby and for comparing the code to authorized codes. An indicator (18) provides an indication whether the identification code corresponds to any of the authorized codes or not. A method of verifying the authenticity of a transponder is also disclosed and claimed.

Abstract: An electronic radio frequency (RF) identification system 10 is disclosed and claimed. The system includes an interrogator 11 and a plurality of RF transponders 12.1 to 12.n. In use, each transponder is operative in response to an interrogation signal 14 to respond with a forward error correctable data message 16.1 including base data encoded as symbol characters in accordance with a forward error correcting code, such as a Reed Solomon Code, and check characters on the base data as defined in the forward error correcting code. The interrogator 11 utilizes data relating to the forward error correcting code, the symbol characters and check characters in the received forward error correctable data message, to reconstruct the base data in the event of corruption of the forward error correctable data message during transmission.

Abstract: An RF electronic identification system (10) is disclosed and claimed. The system includes at least one transponder encoder (14.1) for writing data into a memory arrangement (52) of a selected transponder (1.1) of a plurality of transponders (1.1 to 1.n) adapted to receive data from the at least one encoder. The system further includes at least one verifier (16) for interrogating a selected transponder (1.1) and to read data stored in the transponder. The encoder includes a controller (42) for providing an identification code characteristic of the encoder to form part of the data to be written into the transponder. The verifier includes computing means (56) for extracting the identification code from the data read thereby and for comparing the code to authorized codes. An indicator (18) provides an indication whether the identification code corresponds to any of the authorized codes or not. A method of verifying the authenticity of a transponder is also disclosed and claimed.

Abstract: An electronic radio frequency (RF) identification system 10 is disclosed and claimed. The system includes an interrogator 11 and a plurality of RF transponders 12.1 to 12.n. In use, each transponder is operative in response to an interrogation signal 14 to respond with a forward error correctable data message 16.1 including base data encoded as symbol characters in accordance with a forward error correcting code, such as a Reed Solomon Code, and check characters on the base data as defined in the forward error correcting code. The interrogator 11 utilizes data relating to the forward error correcting code, the symbol characters and check characters in the received forward error correctable data message, to reconstruct the base data in the event of corruption of the forward error correctable data message during transmission.

Abstract: A transponder 14.1 for a radio frequency (RF) identification system comprises an antenna 22.1 having an antenna Impedance (ZA) having a real part (RA) connected to transponder circuitry presenting a load impedance (ZL) having a real part (RL), a ratio (Ra/Rl) of the real part (RL) of the load impedance and the real part (RA) of the antenna impedance having a first value that is bigger than one when the transponder is not transmitting data. During transmission of data the ratio is switched between the first value and a second smaller value.

Abstract: An electronic identification system 100 comprises an interrogator 10 and a plurality of transponders 12, 14 and 16. The interrogator comprises a transmitter 11 for transmitting an interrogation signal to the transponders; a receiver 13 for receiving response signals from the transponders; and a controller 19 for processing response signals received, to identify the transponders by their respective response signals. Each transponder comprises a signature generator 35, 32 for generating a unique signature characteristic of the transponder and intermittently transmits, in responses to the interrogation signal, a response signal including the signature. The interrogator further comprises an acknowledgement signal generator 21 for generating upon reception of a response signal from one of the transponders, an acknowledgement signal to be transmitted by the transmitter 11. The acknowledgement signal comprises the signature, thereby to acknowledge reception of the response signal.

Abstract: A spacer for items includes a waveguide 28.1 for radio frequency signals and a crate 16.1 or pallet. When items 16.1 to 16.9 in an array are spaced with such waveguides, signals from an interrogator 12 of an RF electronic identification system 10 are guided via the waveguide to transponders 14.1 to 14.9 of the system mounted on the items. Response signals from the transponders are similarly guided in the reverse direction, so that the transponders may be read. The spacer, arrangement and methods according to the invention alleviate the problems presented by an RF barrier in prior art systems.

Abstract: A reader arrangement 22 for an electronic identification system includes a plurality of reader heads 22.1 to 22.4 for energizing transponders 28.1 to 28.n to be read, and a controller 29 therefor. The controller 29 switches activation of the reader heads in a multi-phase sequential pattern including a first phase for activating a first set 22.1 and 22.3 of the reader heads and at least one further phase for activating a further set 22.2 and 22.4 of the reader heads. The switching is such that a complete cycle plus at least the first phase of a subsequent cycle is completed within a time period not longer than a reset period of the transponders. The reset period is the period between removal of an energizing signal from a transponder and the transponder re-entering a normal operational mode.

Abstract: A method of reading a plurality of transponders 14.1 to 14.n forming part of an electronic radio frequency identification system 10 comprises the steps of prompting the transponders at 38 to transmit preambles 30 only of respective response digital sequences to a reader 12. The reader then locks onto the preamble 30 transmitted by one of the transponders and immediately causes a mute signal 38 to be broadcast to mute all of the transponders not yet transmitting. The reader then transmits during a first time window 42 a first command 40 to cause the one transponder to transmit a remainder of the sequence. Having received and read the remainder, the reader transmits a second command 44 during a second time window 46 to cause the one transponder to switch to a sleep mode wherein the one transponder no longer transmits any part of the sequence, and to unmute the muted transponders.