Showing papers by "Intermec published in 2007"

Differential RCS of RFID tag

Abstract: The differential radar cross-section (RCS) of an RFID tag is an important parameter which determines the power of the modulated backscattered tag signal. The vector differential RCS of an RFID tag as seen by the reader is analysed and, for the first time, compared with experimental results in UHF band.

An Ultra-Low-Power Long Range Battery/Passive RFID Tag for UHF and Microwave Bands With a Current Consumption of 700 nA at 1.5 V

Abstract: We present for the first time, a fully integrated battery powered RFID integrated circuit (IC) for operation at ultrahigh frequency (UHF) and microwave bands The battery powered RFID IC can also work as a passive RFID tag without a battery or when the battery has died (ie, voltage has dropped below 13 V); this novel dual passive and battery operation allays one of the major drawbacks of currently available active tags, namely that the tag cannot be used once the battery has died When powered by a battery, the current consumption is 700 nA at 15 V (400 nA if internal signals are not brought out on test pads) This ultra-low-power consumption permits the use of a very small capacity battery of 100 mA-hr for lifetimes exceeding ten years; as a result a battery tag that is very close to a passive tag both in form factor and cost is made possible The chip is built on a 1-mum digital CMOS process with dual poly layers, EEPROM and Schottky diodes The RF threshold power at 245 GHz is -19 dBm which is the lowest ever reported threshold power for RFID tags and has a range exceeding 35 m under FCC unlicensed operation at the 24-GHz microwave band The low threshold is achieved with architectural choices and low-power circuit design techniques At 915 MHz, based on the experimentally measured tag impedance (92-j837) and the threshold spec of the tag (200 mV), the theoretical minimum range is 24 m The tag initially is in a "low-power" mode to conserve power and when issued the appropriate command, it operates in "full-power" mode The chip has on-chip voltage regulators, clock and data recovery circuits, EEPROM and a digital state machine that implements the ISO 18000-4 B protocol in the "full-power" mode We provide detailed explanation of the clock recovery circuits and the implementation of the binary sort algorithm, which includes a pseudorandom number generator Other than the antenna board and a battery, no external components are used

Platform tolerant RFID tag antenna

Abstract: A passive radio-frequency identification (RFID) tag antenna for UHF applications is proposed. An inductively coupled feed for the tag, employed previously in an earlier design, is modified to realize a new RFID tag antenna. A ground plane is used in the design to make the tag antenna platform-tolerant. The read range and percentage power transfer of the tag antenna are studied.

Platform-tolerant Design for an RFID Tag Antenna

Abstract: In this paper, the previous design of an inductively-coupled feed for an RFID tag antenna is modified to realize a platform-tolerant characteristic. In the new feed, parts of the feed line are connected directly to the radiating element to realize a platform-tolerant RFID tag antenna, which comprises a microstrip patch. Since there is a ground plane underneath the patch and the feedline, the performance of the tag is essentially independent of the surface upon which the tag is mounted. This desirable feature of the tag is confirmed by the measured results presented herein.

Keypad overlay membrane

Abstract: A keypad overlay membrane provides guidance to a user in selecting an intended key to strike and avoiding striking unintended keys. In one arrangement the overlay membrane is formed by a continuous thin-walled sheet having an outwardly-facing surface and an opposed inwardly-facing surface. Formed into the thin-walled sheet are a first array of raised members and a second array of channels. The raised member array is laid out in a configuration for positioning atop individual keys of the electronic device keypad, with the channel array located between the raised member array. Upon placing the overlay membrane onto keypad, the user can apply a sufficient inwardly directed force to one of the raised members to induce movement of the respective key underlying and aligned with the particular raised member. In another arrangement, an array of concave depressions substitutes for the raised member array and channel array.