Patent ID: 7075901

Claim:
A communication system comprising: an interrogator configured to output a radio frequency signal; and a communication device configured to communicate with the interrogator and including: a receive antenna configured to receive the radio frequency signal; a backscatter antenna; a switch configured to selectively short-circuit a plurality of leads of the backscatter antenna providing a first load impedance of the backscatter antenna and a second load impedance of the backscatter antenna less than the first load impedance; and communication circuitry configured to control the switch to implement backscatter communications using the backscatter antenna during a transmit mode of operation of the communication device, and to provide the switch in an open state during a receive mode of operation of the communication device; and a transformer coupled with the communication circuitry and the backscatter antenna and configured to transform a load impedance of the backscatter antenna from the first load impedance to the second load impedance during the receive mode of operation of the communication device to provide beam forming of the backscatter antenna and the receive antenna.