Artificial Surface Based Wireless Power Transfer

In order to alleviate energy crisis and find alternative energy for the sustainable development of human beings, scientists put forward the concept of space solar power satellite (SSPS). In this paper, we introduce a new wireless power transmission method based on perfectly matched layer (PML). We embed rectifying diodes into the well-designed metamaterial units and arrange these units into a periodic array. This rectifying surface can simultanously realise an almost perfect impedance matching to the air and the rectifying circuits. Meanwhile, the rectifying surface can automatically achieve harmonic suppression, which ensures a concise structure.A rectifying surface sample with1/40λ thickness is then tested in our anechoic chamber. The result shows that the rectifying surface has power absorption of99.92%under the normal incidence of a plane electromagnetic wave with power density of0.1mW/cm2. The suppression of second harmonis is56.16dB and the rectifying efficiency matches well with the result of simulation. Due to an additional layer of DC power combiner, all metamatrial units output DC power will be combined before transmission.The rectifying surface can also absorb the circular polarized electromagentic wave if we change the geometric structure of every unit. Besides, if the DC power combiner is replace by an AC power combiner, fewer rectifying circuits will be needed and the recitying efficiency will also increase with the increasing microwave input power of rectifying diodes.