| Microwave power transmission(MPT)technology breaks through the limitation of cable in the traditional energy transmission process,realizes the point-to-point energy transmission mode in space.It has far-reaching influence on the transformation of human lifestyle,and has attracted the attention of many domestic and foreign scholars in recent years.Although microwave power transmission technology was originally used to realize space solar power transmission,it has been gradually applied in various fields,such as radio frequency identification,sensor power supply,drone driving and so on.Its application research mainly focuses on wireless charging,microwave energy collection and wireless power transmission.Rectifier antenna,as a key component in various applications,has naturally become one of the key research areas of microwave energy transmission technology.There are still many challenges for the rectifier antenna used for microwave energy collection,such as the balance between the size and efficiency of the antenna,the relatively weak microwave energy of a single band in the received environment,and so on.After researching related literatures at home and abroad,this paper attempts to improve the above problems by designing dual-band rectennas.The main contents of the article are as follows:According to the radiation principle of microstrip antenna,the theory and design method of dual-band microstrip antenna are studied and analyzed.Based on the analysis and research of dual-band antenna,the conventional monopole antenna is improved.A dual-band omnidirectional monopole receiving antenna is designed and implemented.Its working bandwidth covers the WLAN band(2.4GHz and 5.8GHz),so as to collect electromagnetic energy in the widely distributed WLAN band.On this basis,the working bandwidth is further expanded,and a broadband omni-directional receiving antenna is designed.The size of the antenna is only 10 mm,and it has good omni-directional characteristics in the 2.02-5GHz band.Finally,the research on miniaturized dual-band receiving antenna is carried out.A dual-band antenna is designed in the form of a floor slot.The antenna is small in size and simple in structure.The working principle of microwave rectifier circuit is studied.The theoretical analysis and comparison of the characteristics of the Schottky diode are carried out,and the rectifier diode suitable for the dual-frequency rectifying antenna is selected.The performance of three typical structures of the rectifier circuit is simulated and analyzed.Finally,the single-tube parallel and double-tube double-voltage structure with high rectification efficiency are selected for circuit design.Through the research on the principle of impedance matching,the design method of dual-frequency impedance matching network is focused on,and design the matching network for single-tube parallel structure and voltage doubler rectifier circuit respectively.The 2.4GHz single-frequency rectifier circuit is realized and designed.Then design a dual-frequency voltage doubler rectifier circuit in the WLAN band,the rectification efficiency of the two frequency bands can reach 65% and 44%.After completing the design of the rectenna,the microwave energy transmission experiment was initially explored.The experimental results show that in the 2.4 GHz band,the maximum DC voltage output of the slot rectenna at-10 dBm received signal strength is 159 mV,which can supply power to the chip for energy harvesting.And the test results also show that a good match between the receiving antenna and the rectifier circuit is especially important for the performance of the rectenna. |
PDF Full Text Request