RFID memory devices

A method of reading data recorded on a memory device, the memory device including N arrays of one or more resonant members, the resonant members in each array extending in a common direction which is different from the common direction in which resonant members in other arrays extend, the method including the steps of:

• (a) for each of at least N+1 calibration directions in a plane containing the resonant members:
• (i) applying a magnetic field across the resonant members in that direction,
• (ii) applying at least a first excitation signal to the memory device,
• (iii) receiving at least a first response to the excitation signal, and
• (iv) analyzing the response in order to detect changes in the impedance of the electrical equivalent circuit of the memory device,
• (b) determining the angular offset between a first calibration direction and the common direction of a first array from the detected changes in impedance, and
• (c) re-orienting the magnetic field so as to selectively read data encoded in one of the resonant arrays.

A method of reading data recorded on a memory device, the memory device including N arrays of one or more resonant members, the resonant members in each array extending in a common direction which is different from the common direction in which resonant members in other arrays extend, the method including the steps of:

• (a) for each of at least N+1 calibration directions in a plane containing the resonant members:
• (i) applying a magnetic field across the resonant members in that direction,
• (ii) applying at least a first excitation signal to the memory device,
• (iii) receiving at least a first response to the excitation signal, and
• (iv) analyzing the response in order to detect changes in the impedance of the electrical equivalent circuit of the memory device,
• (b) computing the impedance change caused by resonant members in each array, when the magnetic field is oriented perpendicularly to the common direction in which those resonant members extend, from the detected changes in impedance.