An impedance matching network for high efficiency dual-band rectifier

• Main Author: Zhang, Dingyi
• Other Authors: Muhammad Faeyz Karim
• Format: Thesis-Master by Coursework
• Language: English
• Published: Nanyang Technological University 2020
• Subjects: Engineering::Electrical and electronic engineering
• Online Access: https://hdl.handle.net/10356/140921
• Institution: Nanyang Technological University

Microwave wireless power transmission (MWPT) technology is one of the wireless power transmission (WPT) technologies and it is widely used in space solar power station (SSPS), space aircraft energy supply, wireless sensor network (WSN) and so on. Rectenna is a vital component of the MPT system and it is used to receive the electromagnetic power and convert it into DC power. The obtained DC power can supply the energy for some other electronic equipment. Rectenna is composed of antenna and rectifier. Because of the nonlinear characteristic of the microwave diode, it is difficult to design high efficiency multiband rectifier and high efficiency wide input power range rectifier circuit. In addition, the radiation of the harmonic components of the diode, the polarization mismatch between the transmitting antenna and the receiving antenna also can lead to the decreasing of the rectenna efficiency. Therefore, high efficiency multiband rectifier, especially the dual-band impedance matching network is the main content of this paper. By studying the basic principle of rectifying circuit, it proposed the methods to design a rectifying circuit. At the same time, with making comparison of several different structures of rectifying circuit, it concluded the advantages and disadvantages of different rectifying circuit structures. Then the formulations of voltage and current of the rectifying diode in the rectifying circuit was inferred and the influence of the rectifying diode on the rectifying efficiency was given. Finally, it proposed the requirement of rectifying diode for low input power rectifying circuit and the formulations to calculate the input impedance of diode and the efficiency of the rectifying circuit, which made the preparation for the designing of rectifying circuit for low input power. When introducing the relevant principles of impedance matching, several basic structures to match different impedances was proposed and was simulated in advance design system (ADS). A dual-band matching network matched the impedance of the rectifying diode at 0.915 GHz and 2.4 GHz. First, the circuit was simulated in ADS and then use HFSS to do the FEM simulation. Then we find the practical value of the input impedance is different from the calculation. When the input power is 15dBm, the efficiency at both frequency are 77.3% and 73.5%. The return loss in circuit simulation is lower than 15dB and the electromagnetic simulation is lower than 30dB. The dual-band rectifier circuit designed in this paper can achieve high efficiency in two frequency bands, and the size of the rectifier circuit is smaller than the size of the rectifier circuit proposed in some related literature. These two advantages are very important for wireless energy transmission systems. Therefore, it can be applied to high-efficiency multi-band microwave wireless energy transmission systems. Keywords: microwave power transmission, rectifying circuit, dual frequencies, impedance matching