Abstract
Rectenna is an important receiving circuit in wireless power transmission system. It can receive microwave power from antenna part and then transmit it to rectifier part for rectifying to direct current power. Therefore, rectennas can be widely used such as wireless power supply. In the following thesis, rectenna is divided into two main structures, antenna and rectifier, for more detail discussed. Part I describes FR4-fabricated quasi-yagi antenna which is fed by microstrip line. This kind of antenna, which is a development of dipole antenna, has a simple and easy understood structure. It utilizes reflect element and direct element to make its radiation pattern become narrower; therefore, its directivity and gain of quasi-yagi antenna can be higher. However, in order to narrow down the Half Power Beam-width of antenna, and improve antenna gain, quasi-yagi antenna array is proposed by using Wilkinson Power Divider. The gain pattern of antenna array can be calculated and is predictable with array factor. In this way, quasi-yagi antenna array can improve its directivity and gain to a higher level, and surely have a narrower Half Power Beam-width. The quasi-yagi antenna and its combination with Wilkinson power divider can be applied to wireless network system in the frequency of 2.4 GHz. The design process and measured results are shown in the end of Part I. Part II introduces FR4-fabricated rectifier including three different structures on purpose, and rectenna, which is composed of rectifier and antenna. Rectifiers can be separated into two types, 1-stage and 2-stage voltage multiplier. There are two different 1-stage voltage multiplier structures due to its well-matched point at different input power. Transition efficiency can be improved with match at higher input power. Besides, high input power can turn on diodes in 2-stage voltage multiplier so that it can acquire higher output voltage and efficiency. The last structure, rectenna, can not only transform microwave signal to direct signal providing to the following circuits but also measure antennas’ radiation pattern.