Metamaterial-inspired GPS L1 rectennas

Several GPS L1 (1.5754 GHz) rectennas have been developed for low input power applications. These rectennas incorporate high efficiency, electrically small, metamaterial-inspired near field resonant parasitic antennas, and a Schottky diode that has a low built-in voltage, and a resistor as the load. For the low, 0.0 dBm (1.0 mW), input power level to the protractor-based rectennas, the measured rectifying efficiencies of the larger (ka = 0.808) and 25% smaller (ka = 0.604) protractor versions are, respectively, 78.0% at 1.5754 GHz and 67.9% at 1.55 GHz. Similarly, for the 0dBm input power to an S-inclusion-based rectenna (ka∼0.611) that again is matched directly to the input impedance of the rectifying circuit, the simulated and measured rectifying efficiencies were, respectively, 75.7% and 79.6%. It will be demonstrated that the simulated and measured results are in good agreement in all cases.