| CPC H01Q 3/267 (2013.01) [G06K 7/10297 (2013.01); H04B 5/20 (2024.01); H04B 17/21 (2015.01)] | 17 Claims |

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1. A radio frequency identification (RFID) device, comprising:
a transmitter;
a matching device; and
a receiver that includes an estimation unit and at least one receiver input coupled to the matching device;
wherein the transmitter is coupled via the matching device to the at least one receiver input;
wherein the transmitter is configured to transmit a transmitter signal, which is looped-back through the matching device to the at least one receiver input, and wherein the looped-back transmitter signal at the at least one receiver input corresponds to a calibration signal;
wherein the receiver is configured to receive the calibration signal from the matching device at the at least one receiver input, to sample an amplitude of the calibration signal in order to produce a sampled amplitude of the calibration signal, to obtain an I-path signal and a Q-path signal based on the sampled amplitude, and to estimate, by the estimation unit, an estimated phase shift through the matching device of the calibration signal based on the obtained I-path signal and the obtained Q-path signal; and
wherein the RFID device is configured to adjust at least one of a transmitter phase shift and a receiver phase shift in order to compensate at least partially for the estimated phase shift.
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