Antenna designs for wide-band, orientation insensitive RFID devices

A method for operating an RFID device, the method comprising:

• providing a first resonator comprising a sheet and a conductive member;
• positioning a second resonator within the first resonator, the second resonator comprising a loop conductor and an RFID chip, wherein positioning the second resonator comprises placing the second resonator within the first resonator, leaving a gap between the first resonator and the second resonator;
• exposing the first resonator and the second resonator to an RF signal;
• feeding RF power to the second resonator via a feeding structure, wherein the feeding structure is connected to the loop conductor;
• inducing the RF power to the first resonator coupled to the second resonator;
• exciting the first resonator and the second resonator to operate at an operating frequency;
• tuning the first resonator using the conductive member and the second resonator using the RFID chip to resonate at the operating frequency;
• and
• radiating an output RF signal in response to the fed RF signal.