Electromagnetic modeling and analysis of rectifier antennas

Electromagnetic modeling, design, development, and analysis of a zero-bias rectifier antenna (rectenna) are studied for RF energy harvesting purposes. A specific Schottky diode is selected for its desired parameters and its equivalent nonlinear circuit model with spice and scattering parameters are used to design the zero bias rectifier. The rectifier model is generated using nonlinear microwave and electromagnetic simulation tools and RF and DC responses are obtained, then input impedance is matched to 50ohms by using reactive elements to reduce the reflected RF power at the rectifiers´ input. On the other hand, a miniaturized planar inverted F-shaped antenna (PIFA) with an input impedance of 50ohms is designed on a microstrip substrate and its response is simulated using a 3-D simulation tool. Once the circuits are manufactured, (i) different RF signals levels are applied at input of the rectifier and converted DC output voltage measurements are tabulated, (ii) the antenna´s gain and radiation pattern are given and s-parameters are measured using a network analyzer, (iii) rectenna performance is measured and the RF energy harvesting potential is presented.