Abstract: The circuitry introduced in this invention selectively slows down the functioning of an electronic circuit maintaining a particular state for a prolonged period of time. This circuitry is used not only to achieve the desired effect in maintaining security from electronic thieves trying to circumvent codes but also in other applications such as enabling a circuit to continue to function in the event of a brief loss of power. For example, in an RFID system, if a reader is frequency hopping, a tag loses power for as long as about 400 milliseconds when the reader changes to other frequencies. In a preferred embodiment, the disclosed circuitry is used in conjunction with a destruct sequence.

Abstract: The circuitry introduced in this invention selectively slows down the functioning of an electronic circuit maintaining a particular state for a prolonged period of time. This circuitry is used not only to achieve the desired effect in maintaining security from electronic thieves trying to circumvent codes but also in other applications such as enabling a circuit to continue to function in the event of a brief loss of power. For example, in an RFID system, if a reader is frequency hopping, a tag loses power for as long as about 400 milliseconds when the reader changes to other frequencies. In a preferred embodiment, the disclosed circuitry is used in conjunction with a destruct sequence.

Abstract: The circuitry introduced in this invention selectively slows down the functioning of an electronic circuit maintaining a particular state for a prolonged period of time. This circuitry is used not only to achieve the desired effect in maintaining security from electronic thieves trying to circumvent codes but also in other applications such as enabling a circuit to continue to function in the event of a brief loss of power. For example, in an RFID system, if a reader is frequency hopping, a tag loses power for as long as about 400 milliseconds when the reader changes to other frequencies. In a preferred embodiment, the disclosed circuitry is used in conjunction with a destruct sequence.

Abstract: The circuitry introduced in this invention selectively slows down the functioning of an electronic circuit maintaining a particular state for a prolonged period of time. This circuitry is used not only to achieve the desired effect in maintaining security from electronic thieves trying to circumvent codes but also in other applications such as enabling a circuit to continue to function in the event of a brief loss of power. For example, in an RFID system, if a reader is frequency hopping, a tag loses power for as long as about 400 milliseconds when the reader changes to other frequencies. In a preferred embodiment, the disclosed circuitry is used in conjunction with a destruct sequence.

Abstract: A tag receives a first code transmitted by an RFID reader. The first code is compared with a second code stored within the tag. If the first code and the second code match, the tag transmits a third code to the RFID reader.

Abstract: An identification system includes a reader and one or more tags. The reader identifies tags such as radio frequency (RF) tags. The system divides a number space into n bins, wherein each bin is associated with m unique bits of the number space, and the number space contains the identification codes of the tags. A command is issued to test v bits of the number space. A response is received from a tag, wherein the response occurs when a first portion of an identification code of the tag matches the v bits of the number space, a timing of the response corresponds to a particular bin and m unique bits associated with the particular bin correspond to a second portion of the identification code.

Abstract: The circuitry introduced in this invention selectively slows down the functioning of an electronic circuit maintaining a particular state for a prolonged period of time. This circuitry is used not only to achieve the desired effect in maintaining security from electronic thieves trying to circumvent codes but also in other applications such as enabling a circuit to continue to function in the event of a brief loss of power. For example, in an RFID system, if a reader is frequency hopping, a tag loses power for as long as about 400 milliseconds when the reader changes to other frequencies. In a preferred embodiment, the disclosed circuitry is used in conjunction with a destruct sequence.

Abstract: An identification system includes a reader and one or more tags. The reader identifies tags such as radio frequency (RF) tags. The system divides a number space into n bins, wherein each bin is associated with m unique bits of the number space, and the number space contains the identification codes of the tags. A command is issued to test v bits of the number space. A response is received from a tag, wherein the response occurs when a first portion of an identification code of the tag matches the v bits of the number space. A timing of the response corresponds to a particular bin and m unique bits associated with the particular bin correspond to a second portion of the identification code.

Abstract: A portable communication device uses a first electrostatic antenna element and a second electrostatic antenna element and circuitry which is coupled to the first antenna element and to the second antenna element and which derives operating power from an electrostatic field in the vicinity of the first and second antenna elements. The electrostatic field may be provided by an array of exciter elements containing both horizontal and vertical exciter elements so that at some point as a communication device is moved across the exciter antenna array, the device will have sufficient power coupled to it to power up and become operational.

Abstract: An identification system includes a reader and one or more tags. The reader identifies tags such as radio frequency (RF) tags. The system divides a number space into n bins, wherein each bin is associated with m unique bits of the number space, and the number space contains the identification codes of the tags. A command is issued to test v bits of the number space. A response is received from a tag, wherein the response occurs when a first portion of an identification code of the tag matches the v bits of the number space. A timing of the response corresponds to a particular bin and m unique bits associated with the particular bin correspond to a second portion of the identification code.

Abstract: A key (10) includes a transceiver core (12) that couples to antenna electrodes that include all or part of a key shank (11) and an electrically conductive surface (16). The transceiver core (12) utilizes these electrodes (11 and 16) to capacitively transceive information with a reader (41). The reader (41) may, in turn, utilize all or part of a keyed lock cylinder (43) as an antenna electrode.

Abstract: A radio frequency identification tag system (10) utilizes a radio frequency identification tag (16) that includes stored information. The tag includes an antenna element (28) and a common electrode (26), the common electrode being coupled to ground (70). The antenna element electrostatically receives an exciter signal (30) from a proximately-located exciter (12). Upon receiving the exciter signal, the tag becomes energized, thereby causing it to generate a read signal (32) based on the stored information. The antenna element then electrostatically sends the read signal to a proximately-located reader (14), which detects the stored information. Both energy and data are capacitively coupled by virtue of the unbalanced nature of the network, thus resulting in decreased coupled impedance.

Abstract: A radio frequency identification tag (100) in accordance with the present invention includes a first antenna element (112), a second antenna element (114) and a radio frequency identification circuit (116). The first antenna element (112) is electrically isolated from the second antenna element (114). The radio frequency identification circuit has a first pad (230) and a second pad (232). The first and second pads of the radio frequency identification circuit are coupled, respectively, to the first and second antenna elements. The radio frequency identification circuit includes a load modulation circuit (222) coupled to at least one of the first or second pads to produce a load modulated signal on at least one of the first or second pads that varies from a first amplitude to a second amplitude. The load modulation circuit has a modulation impedance and a predetermined voltage threshold that an input signal must exceed before the modulated signal is produced.