Patent ID: 8249524

Claim:
A circuit comprising: an antenna interface to couple to an antenna designed to communicate with external antennas by inductive coupling; a transmitter portion to generate a transmit wireless signal to be transmitted by the antenna; a shunt capacitor; a receiver portion to receive and process a receive wireless signal from the antenna; and a switch operable in a first mode and a second mode, wherein the switch couples the shunt capacitor in parallel with the antenna in the second mode, the switch decoupling the shunt capacitor from the antenna in the first mode, wherein the transmitter portion is designed to transmit the transmit wireless signal in a transmit interval, and the receiver portion is designed to receive the receive wireless signal from the antenna in a receive interval, wherein the switch is operable in the first mode in the transmit interval and in the second mode in the receive interval, whereby the switch couples the shunt capacitor in parallel with the inductance of the antenna to form a shunt resonant circuit in the receive interval to maximize a voltage generated at an input terminal of the receiver portion in the receive interval, the switch to decouple the shunt capacitor from the inductance of the antenna in the transmit interval to enable maximization of a current generated in the antenna in the transmit interval.