AOTF-NIR宽带功率超声换能器阻抗匹配网络的设计与优化

摘要

随着近红外声光可调滤波器(Near Infrared Acousto-Optic Tunable Filter,AOTF-NIR)光谱成像技术在深空探测的广泛应用,超声换能器作为AOTF-NIR核心部件,对其工作带宽、光谱衍射效率及功率效率提出了更高的要求.超声换能器在不同频率下具有不同的输入阻抗,当驱动信号源输出阻抗与换能器输入阻抗失配时将会产生能量损耗,导致无法把功率最大限度的传递给换能器,从而使AOTF-NIR光谱衍射效率降低,影响光谱灵敏度.该文通过射频电路先进设计系统(Advanced Design System,ADS)仿真及实验测试,运用滤波器网络理论,采用LC无耗储能元件设计了一种带通型宽带匹配网络.最终在60-120MHz带宽范围内阻抗匹配网络的回波损耗S11>-29.8dB,阻抗匹配网络功率效率达到90%以上.通过不断地微调优化匹配阻抗值及LC参数值,以此来提高光谱衍射效率,使光谱衍射效率最高达90%以上,提高了在620-1150nm波段内的光谱灵敏度及光谱成像清晰度.%With the AOTF-NIR spectral imaging technology is widely used in the deep space exploration,ultrasonic transducer as AOTF-NIR core components for it''s operating bandwidth,spectrum diffraction efficiency and power efficiency,put forward higher requirements.It has different input impedances at different frequencies.When the drive signal source output impedance and ultrasound transducer input impedance mismatch will produce energy losses.Resulting in unable to the maximum power delivered to the transducer,so that the AOTF-NIR spectroscopy diffraction efficiency is reduced,affecting spectral sensitivity.The article by ADS simulation and experimental testing,applied on filter network theory and used LC lossless energy storage element and designed one kind of bandpass broadband matching network.Finally,impedance matching network return loss S11>-29.8dB within the 60-120MHz bandwidth,impedance matching network power efficiency is more than 90%.By constantly fine-tuning and optimizing matching the impedance values and LC parameter is to improve the spectral diffraction efficiency and spectral diffraction efficiency is more than 90%.Improved spectral sensitivity and spectral imaging clarity within the 620-1150nm band.