Research On Full Polarized Microwave Power Receiver System

Radio frequency based wireless power transfer (WPT) offers a new energy transfer approach to supply non-accessible fixed and mobile system, which can work over distance from several wavelengths to thousands of kilometers. It shows a great applicable prosperity in the field of Space Solar Power Satellite (SSPS) and spacecraft power transmission, and its application towards wireless powering of mobile computing devices and sensors also attracts sustained interests over recent decades. These widespread devices could be powered by a microwave feeding source, or collect EM energy from ambient environment, thus improving the portability and self sustainability. In the above applications, the polarization direction can be diverse, therefore the absorbing capability of single polarized receiving equipments is limited.This dissertation presents a microwave energy reception approach to receive arbitrarily polarized low density microwave radiation. The newly designed rectifying antenna integrates array of dual-linear polarized resonant cells with branch coupler. The two orthogonal components of received RF signals with equal phases but unequal amplitudes can be redistributed into two outputs with equal amplitudes but unequal phases. In such a case, the input power into the rectifying circuits would be invariant and make it work at the best efficiency regardless of the polarization angle of incident EM wave. Passive power combiner is used to increase the input power into rectifier.The fabricated sample operates on the frequency of 2.325GHz. It shows RF-to-DC efficiency ranging from 57.23% to 58.13% at all linear polarization angles, under 0.15 mW/cm2 incident power density, which proves the validity of the scheme. The rectenna could also receive circularly polarized electromagnetic energy, thus realize the reception of full polarization.