Abstract: An antenna apparatus includes a structure configured to mount within a stock race to permit animals to pass therethrough. One or more antenna coils are attached to or within the structure and provide a magnetic field laterally across the structure. The coils may be arranged in a Helmholtz configuration to provide a substantially uniform field in a read zone. The structure may have an open top and the side walls of the structure may be slanted forwards.

Abstract: An animal identification system, including: a race including a pair of opposed walls between which, in use, animals pass, and a floor including one or more steps or sloping sections defining a height change; one or more readers configured to read electronic animal identification devices borne by animals passing along the race; wherein, at least one of the one or more readers is positioned beneath, on top of or within the floor at or near the height change such that, in use, movement of the animals caused by the height change tends to bring the animals' identification devices into closer proximity to that reader.

Abstract: Low noise mixers for use in RFID readers and RFID readers configured to receive data from ISO HDX transponders in accordance with embodiments of the invention are illustrated. One embodiment of the invention receives the HDX FSK signal using a resonant antenna, upwardly mixes the FSK signal to an intermediate frequency, filters the intermediate frequency FSK signal using at least one ceramic bandpass filter, and demodulates the filtered intermediate frequency FSK signal to produce a binary output.

Abstract: Turning now to the drawings, systems and methods for reading RFID transponders utilizing readers in which the Q-factor of the resonant antenna of the reader shifts over the course of the reader's interrogation cycle in response to the detection of data from FDX and HDX RFID transponders in accordance with embodiments of the invention are illustrated. One embodiment having a dynamically adjustable Q-factor, wherein the reader transmits an activation signal configured to activate half duplex and full duplex transponders includes a signal source configured to drive a resonant antenna and a dynamic switching circuit configured to set the Q-factor of the resonant antenna to a first value during the transmission of the activation signal.