V波段多通道辐射计前端关键技术研究

发布时间：2018-01-05 23:26

本文关键词：V波段多通道辐射计前端关键技术研究　出处：《电子科技大学》2016年硕士论文　论文类型：学位论文

【摘要】：氧分子以及水汽分子的谐振吸收作用会对在大气中传播的毫米波造成较大的衰减。其中,氧分子在50-70GHz之间分布有很多谐振吸收线。低层大气的高气压会造成压力展宽效应,而这种效应使很多谐振吸收线相互叠加形成了连续的吸收带。利用V波段多通道辐射计观测大气的这一强吸收带,可以反演出大气的温度廓线,是中小尺度天气实时监测、预报的一种重要手段。因此,本文针对V波段多通道辐射计前端做了如下几方面关键技术的研究。针对需要使用端口为共面线的微波单片集成电路搭建混合集成模块的情况,研究了波导到共面波导的过渡。出于整体结构方面的考虑,分别设计了波导到共面波导的E面过渡和H面过渡,并将两种过渡做成背靠背结构集成在一个模块中。测试结果显示,在V波段全频段内,背靠背过渡结构(包含中间的一段6.6mm长度的共面传输线)的反射系数低于-13dB,插入损耗小于1.1dB。辐射计前端多个通道的分隔需要用分配网络实现。当两个需要分隔的通道没有频段重叠时,分配网络考虑使用分路器;若有重叠频段,分配网络则考虑使用魔T并在其两平分臂后分别加滤波器的形式实现。针对需要的50-60GHz频段,本文仿真设计了一个宽带魔T,仿真结果显示,在50-65GHz的频段内,各端口反射系数小于-20dB,两平分臂隔离度大于28dB。分路器采用H面T接头连接两个波导膜片滤波器的结构实现,仿真结果显示,两个通道内的反射基本小于-15dB,两通道中心频点的隔离度超过40dB。针对用于校准的噪声注入模块,设计了V波段单刀单掷开关。通过在HFSS中建立PIN管的简化物理模型并反复提取参数,设计出的开关可以实现在50-65GHz的频段内插入损耗小于1dB,隔离度大于16dB。检波器将各通道接收到的高频信号转换为便于后端处理的低频信号,是辐射计前端的关键模块。通过在HFSS中建立检波二极管的简化物理模型、设计宽带直流回路、低通滤波器和匹配电路,设计出的零偏置检波器在50-60GHz的频带内电压灵敏度均大于4800mV/mW。
[Abstract]:The resonant absorption of oxygen molecules and water vapor molecules will cause great attenuation of millimeter waves propagating in the atmosphere. There are many resonant absorption lines in the range of 50-70 GHz for oxygen molecules. High atmospheric pressure in the lower atmosphere will cause pressure broadening effect. This effect makes many resonant absorption lines superimposed on each other to form a continuous absorption band. The temperature profile of the atmosphere can be reversed by using the V-band multi-channel radiometer to observe the strong absorption band of the atmosphere. It is an important means of real-time weather monitoring and forecasting in medium and small scale. In this paper, the key technologies of the V band multichannel radiometer front end are studied in the following aspects, aiming at the case that the microwave monolithic integrated circuit with the port as the coplanar line is used to build the hybrid integrated module. The transition from the waveguide to the coplanar waveguide is studied. The E plane transition and the H plane transition from the waveguide to the coplanar waveguide are designed for the consideration of the overall structure. The two transitions are integrated into a single module with back-to-back structure. The test results show that the two transitions are in the full frequency band of V band. The reflection coefficient of a back-to-back transition structure (including a coplanar transmission line of 6.6mm in length in the middle) is less than -13dB. The insertion loss is less than 1.1 dB. The separation of multiple channels at the front end of the radiometer needs to be implemented by a distribution network. When there is no overlap of frequency bands between the two channels that need to be separated, the network considers the use of a splitter. If there are overlapping bands, the distribution network considers the use of magic T and separate filters after its two parallel arms. For the required 50-60 GHz band, a broadband magic T is simulated and designed in this paper. The simulation results show that the reflection coefficient of each port is less than -20dB in the frequency range of 50-65GHz. The isolating degree of two parallel arms is more than 28 dB. The splitter is realized by H plane T junction and two waveguide diaphragm filters. The simulation results show that the reflection in the two channels is less than -15dB. The isolation of the center frequency of the two channels is more than 40 dB. The noise injection module is used for calibration. A V-band single-pole single-throw switch is designed. The simplified physical model of PIN tube is established in HFSS and the parameters are extracted repeatedly. The designed switch can realize the insertion loss of less than 1dB in the frequency band of 50-65GHz. The isolation is greater than 16dB.The detector converts the high-frequency signals received by each channel into low-frequency signals which are easy to process at the back end. It is the key module of radiometer front-end. By establishing a simplified physical model of detector diode in HFSS, the broadband DC loop, low-pass filter and matching circuit are designed. The designed zero-offset detector has a voltage sensitivity greater than 4800mV / mW in the frequency band of 50-60GHz.
【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TH76

【相似文献】