Supersensor (Proprietary) Limited

Data Investments Limited

David Edwin Proctor

Christopher Gordon Gervase Turner

Andries Petrus Cronje Fourie

Johan Dawid Kruger

Christopher Gordon Turner

A reader arrangement for an electronic identification system includes a plurality of reader heads to for energizing transponders to .n to be read, and a controller therefor. The controller switches activation of the reader heads in a multi-phase sequential pattern including a first phase for activating a first set and of the reader heads and at least one further phase for activating a further set and 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.

Reader arrangement for an electronic identification system having a plurality of reader heads for energizing transponders

A dipole antenna comprises a loop as a first pole and an appendage comprising a strip terminating in a pad as a second pole. The circumference of the loop is in the order of one half-wavelength of an operating frequency and an effective length of the appendage is at least 0.15 times the wavelength. The dipole antenna is shorter than conventional half-wavelength dipole antennas, has a better frequency response and the antenna impedance Z is dependent on the position of a feedpoint in the loop . The antenna may be used with transponders for electronic radio frequency identification systems.

Hybrid antenna arrangement for use with electronic identification systems

A transponder 20 for an electronic identification system transponder is characterized in that it presents a high input impedance (&gt;400.OMEGA.) at an input thereof which is directly connected to an antenna 22 with a matched high input impedance. The transponder is aimed at improving the voltage recovered on capacitor C.sub.2 from an interrogation signal and thus the operational range of the system. The modulator 30 of the transponder is arranged to backscatter modulate the interrogation signal at a modulation depth of less than 80%, preferably in the order of 30%. This also results in an improvement of the operational range of the system.

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Gauteng, South Africa

David Edwin Proctor