Optimal Design Of An Antenna Array For The Wireless Power Transmission System

A novel optimal method for the Microwave Power Transmission (MPT) efficiency for the antenna array design is proposed in this thesis. Compared with other methods, the optimization theory for the MPT efficiency takes the mutual coupling effects into the design consideration and gets a more precise focal distance. What’s more, the focused antenna array designed with this method would obtain good near field patterns properties and low sidelobes level as well.A new2.45GHz focused antenna array with16microstrip patch elements designed with the optimal method is studied in this thesis. A feeding network of the focused antenna array with desired excitation distributions is achieved to get the property of electric fields without sidelobes in the Fresnel region. A maximum power transmission efficiency of27.35%is obtained. The focused distance of the maximum intensity of the electric field is10cm away from the antenna array, which is about66%of the design target of15cm. Moreover, focused antenna array with different excitation distributions are compared.A high gain, linear polarized microstrip antenna array with6microstrip patch elements designed with the proposed optimal method for the energy harvesting at915MHz is investigated. Based on the optimization of the MPT efficiency, the feeding network of the antenna array with desired excitation distributions is obtained to achieve the maximum power transmission efficiency with a given antenna configuration, and also to get the property of electric fields without sidelobes on the given plane. As a demonstration, a Light Emitting Diode (LED) is used as the resistive load of the rectifier (a three-stage Dickson charge pump circuit) connected to the antenna array terminal. For a given input power of10dBm fed into a circularly polarized transmitting antenna with6dBi gain, the maximum distances for lighting the LED with receiving antenna array A, B and C are45cm,38cm and51cm, respectively. It also shows the fact that the arrangement of the array element and the size of the antenna array can affect the performance of the antenna array.