天线耦合太赫兹检测器设计与表征

发布时间：2018-04-11 17:03

本文选题：Nb_5N_6 + microbolometer　；参考：《南京大学》2014年硕士论文

【摘要】：高灵敏检测是太赫兹科学与技术发展与应用的关键技术。天线耦合太赫兹检测器作为太赫兹探测器的一种类型已被广泛地使用与研究。Nb5N6 microbolometer阵列器件正是采用天线耦合方式的太赫兹检测器,具有工艺简单、检测灵敏度高,响应时间快,便于集成大规模阵列等优点。然而,在太赫兹波段芯片衬底的厚度与信号的波长相当,受衬底干涉影响,天线耦合探测器的结构设计、性能表征都存在困难。为了能够表征出天线耦合NbsN6 microbolometer的本征特性,规范器件的性能参数,本论文主要针对基于microbolometer的天线耦合太赫兹检测器的设计与表征展开研究,主要内容包括：第一,设计了基于microbolometer的天线耦合检测器的太赫兹天线。太赫兹天线的作用是提高检测器的信号耦合能力,从而帮助提升器件的检测性能。天线设计中主要考虑的问题之一是天线和负载之间的阻抗匹配,阻抗匹配的程度决定了器件的检测性能,如电压响应率。microbolometer的核心部分是基于NbsN6薄膜材料制成的微桥,其室温电阻在0.6K-3K欧姆的范围内,通常自互补平面天线的特征输入阻抗只有60π欧姆,无法满足Mb5N6 microbolometer的结区高阻抗匹配要求。我们仿真设计了一种高阻抗半偶极子天线,频率设计在0.2 THz频段,并计算了天线的输入阻抗,反射系数S11,电流分布等天线特性。同时,我们还研究了天线谐振吸波结构对天线频率以及耦合效果的影响,根据优化设计结果研制的0.2 TH频段的天线耦合NbsN6 microbolometerz阵列芯片,实验测试结果证实该器件在0.22 THz到0.33 THz都有优秀的电压响应。第二,在太赫兹波段,器件结构的映射小于被测量的入射光束的尺寸。天线耦合太赫兹检测器的有效响应特性能够反应天线实际接收的能量。我们提出一种实验方法——去卷积法(Deconvolution method)来测量天线耦合检测器的有效接收面积。用这种方法,表征了天线耦合NbsN6 microbolometer检测器的性能,研究结果显示,microbolometer的有效接收面积,是器件物理尺寸(主要是天线尺寸)的7.4倍,有效电压响应约为直流电压响应的63%。一个偏置在0.19mA,直流电压响应为-760 V/W的microbolometer检测器,实验测得的有效电压响应率为480 V/W。,本实验方法比较客观的反应了器件在实际光学系统中的可利用性能,为太赫兹波段检测器的表征提供了一个有效方法,也为天线阵列单元尺寸设置提供了参考依据。
[Abstract]:High sensitive detection is a key technology in the development and application of terahertz science and technology.As a type of terahertz detector, antenna coupled terahertz detector has been widely used and studied. Nb5N6 microbolometer array device is a terahertz detector with antenna coupling mode. It has the advantages of simple technology, high detection sensitivity and fast response time.Easy to integrate large-scale arrays and other advantages.However, the thickness of the substrate in the terahertz band is the same as the wavelength of the signal. Due to the influence of substrate interference, the structure design and performance characterization of the antenna coupled detector are difficult.In order to characterize the intrinsic characteristics of antenna coupled NbsN6 microbolometer and standardize the performance parameters of the device, this paper mainly focuses on the design and characterization of antenna coupled terahertz detector based on microbolometer. The main contents are as follows: 1.A terahertz antenna based on microbolometer antenna coupling detector is designed.The function of THz antenna is to improve the signal coupling ability of the detector, thus helping to improve the detection performance of the device.One of the main considerations in antenna design is the impedance matching between the antenna and the load. The degree of impedance matching determines the detection performance of the device. For example, the core part of the voltage responsivity .microbolometer is a microbridge based on NbsN6 thin film material.In the range of 0.6K-3K ohm, the characteristic input impedance of the self-complementary planar antenna is only 60 蟺 ohms, which can not meet the high impedance matching requirements of the Mb5N6 microbolometer junction region.A high impedance half-dipole antenna is designed and simulated. The frequency is designed in the frequency range of 0.2 THz. The antenna characteristics such as input impedance, reflection coefficient S11 and current distribution are calculated.At the same time, we also study the effect of antenna resonant absorbing structure on antenna frequency and coupling effect. A 0.2 th band antenna coupled NbsN6 microbolometerz array chip is developed based on the optimized design results.The experimental results show that the device has excellent voltage response from 0. 22 THz to 0. 33 THz.Second, in terahertz band, the structure mapping of the device is smaller than the size of the measured incident beam.The effective response characteristics of the antenna coupled terahertz detector can reflect the actual received energy of the antenna.An experimental method, Deconvolution method, is proposed to measure the effective receiving area of antenna coupled detectors.The performance of the antenna coupled NbsN6 microbolometer detector is characterized by this method. The results show that the effective receiving area of the microbolometer is 7.4 times of the physical dimension of the device (mainly the antenna size), and the effective voltage response is about 63 times of the DC voltage response.A microbolometer detector with a bias of 0.19 Ma and a DC voltage response of -760 V / W is obtained. The effective voltage response rate measured in the experiment is 480 V / W. this experimental method objectively reflects the availability of the device in the practical optical system.It provides an effective method for the characterization of terahertz band detector, and also provides a reference for the antenna array unit size setting.
【学位授予单位】：南京大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TN820

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