Design and Development of High Efficiency Rectenna at 24 GHz for Wireless Power Transfer

An efficient design of rectenna at 24GHz which can tolerate power dependent load variation and provide better performance over a wider range of loads for wireless power transfer application, is proposed in this article. The proposed design involves class-F structure to reduce the diode conduction loss over a cycle, and a transmission line resistance compression network (TLRCN) to efficiently deal with the load variation. To reduce the losses further, the concept of on-antenna power combining is explored and one single element dual port microstrip loop antenna having peak gain of more than 5 dBi is designed at 24GHz. A peak efficiency of 66% is achieved at 19dBm input power for the combined rectenna at 24GHz. For a resistive load variation of $(30-120)\Omega$, the final input impedance variation of (38-57) $\Omega$ is observed.