| Wireless energy transmission technology(that is,microwave wireless energy)and wireless information transmission technology(that is,wireless communication)are two major applications derived from the characteristics of electromagnetic wave radiation.Microwave wireless energy transmission technology can be widely used in portable electronic equipment,implantable medical equipment,smart home,wireless sensor network,electric vehicle,space solar power station,unmanned aerial vehicle,airship,etc.Wireless communication technology also plays an important role in portable electronic equipment.Besides,it can also be used in military,medical,aerospace and other fields,providing convenience for people’s life and work.The common core indicators involved in these two technologies are system transmission efficiency.In order to achieve high efficiency transmission,it is necessary to study the power devices in the transmission system,including the rectenna and circuit as well as the power amplifier.Rectenna is a key device to transfer RF to DC.It usually consists of rectifier and receiving antenna.Power amplifier is a key device used to convert low power RF signals into high power signals.In different application scenarios,the working frequency,power range and load are different.However,most rectifier circuits are designed for a single performance index dimension(including operating frequency,power range or load)with high efficiency,and their theories and methods are difficult to meet the needs of multiple indicators at the same time.For receiving antenna,in the wireless energy transmission system(especially the wireless energy harvesting),it is necessary to receive the unknown polarization direction and the wide incidence direction efficiently.Therefore,it is very important to design an efficient antenna with wide band beam and insensitive polarization reception.For power amplifier,it often suffers from the problems such as low efficiency at power back-off region,narrow band width and large size.To this end,this paper carries out research on high-efficiency microwave millimeter wave key power devices for wireless transmission of energy and information,including rectifier,rectenna,broadband Doherty power amplifier(DPA)chips at sub-6GHz and millimeter wave.The special research results are as follows:1.In the rectifier,in response to the current research that has rarely expanded the frequency and power range at the same time,this paper conducts generalization and bandwidth expansion of the traditional impedance compressed network theory,and proposes a rectifier based on wideband impedance compression network.In the frequency range of[1.0 GHz,2.7 GHz]and input power range of[-6.2 d Bm,13 d Bm],the rectification efficiency exceeds 70%of the peak value.At the same time,this article also proposes a dual T-type parallel impedance manipulation network.By adjusting the impedance of sub-branches at each node,the wideband and wide-power rectification matching performance from 1.7 GHz to 2.6 GHz can be achieved.In addition,a rectifier circuit based on Lange coupled is proposed to recycle the reflected power,achieving the performance of more than 70%of the peak rectification efficiency over a wide relative bandwidth of 91.9%(from 1.0 GHz to 2.7 GHz)and a wide power range of 17.8 d B(from 5.2 d Bm to 23 d Bm).The related research is published in IEEE Transactions on Microwave Theory and Techniques(Top journals in microwave filed)and some other conferences.2.For the rectenna,aiming at the different performance requirements of rectenna in different application scenarios,this paper firstly designs a six-port coupling network based on Lange coupler,and proposes a rectifier with wide bandwidth and insensitive polarization incidence.In addition,a wideband wide-beam dual-polarized antenna is proposed based on the metal-wall coupling method,which is combined with the rectifier to form the rectenna.In this way,it achieves the rectification effect of broadband(1.7GHz to 2.5GHz),wide power range(the rectification efficiency stays above 50%of the peak value from-7 d Bm to 15 d Bm),wide incidence Angle(half power beam width is greater than 100°)and full polarization reception(efficiency fluctuation is less than 4%within 360°polarization rotation range)at the same time.It is widely applicable to a variety of application scenarios.Related researches have been published in IEEE Transactions on Microwave Theory and Techniques(Top journal in Microwave field)and IEEE Transactions on Industrial Electronics(a Top journal in industrial electronics).3.For wideband DPA IC in sub-6GHz band,aiming at the problems of low power amplifier backdown efficiency,narrow band width and large size,this paper analyzes and compares two kinds of wideband Doherty power amplifier output combiner,and proposes the equivalent method of output transformer,so as to achieve miniaturization and wideband characteristic.Ga As HBT is used to construct broadband Doherty power amplifier chips based on current-combined and voltage-combined method.The working frequency range is from 3.3 GHz to 4.2GHz,and the overall size of the chip are 1.6×3.85mm~2 and 1.7×2.7mm~2,respectively.When the average output power is 30 d Bm,the measured PAE of the current-combined broadband Doherty power amplifier chip is from 26.2%to 30.3%.The corresponding ACLR is less than-32.1d Bc,which can improve the efficiency at power back-off region while maintaining good linearity.It can be applied to the RF front-end modules of mobile phones.The related researches have been submitted to IEEE Transactions on Circuits and Systems II:Express Briefs.4.For wideband DPA IC in millimeter wave band,aiming at the large parasitic effect and large size of the traditional power amplifier in the millimeter wave band,two broadband Doherty power amplifier chips working at 24-33 GHz and 37-43.5 GHz are constructed.They are based on the transistor parasitic capacitance compensation,as well as matching and load modulation function fusion method.The chip sizes are 2.25×1.65 mm~2 and 3.3×1.5 mm~2,respectively.0.1-μm Ga N MMIC technology is adopted.At the saturation power 32 d Bm,the corresponding PAEs are greater than 30.9%and 29.6%,respectively,and when the power is reduced by 6 d B,the corresponding PAEs are greater than 21.1%and 18%,respectively,which can be applied to the millimeter wave wireless communication system,and the comprehensive performance is excellent in the current relevant research work. |
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