web前端-V波段多通道辐射计前端关键技术研究.pdf

摘要

I

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

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。

ABSTRACT

II

ABSTRACT

The resonance absorption by oxygen and water vapor will lead to a large

attenuation when the millimeterwave propagating in the aerosphere. As for oxygen,

there are many resonance absorption lines distributing over 50 to 70GHz. The high

pressure of the lower atmosphere can cause the effect of pressure broadening, which

will lead to a lot of overlap of resonance absorption lines with each other to form a

consecutive absorption band. The temperature profiles of the aerosphere can be deduced

by observing this strong absorption band with the V-band multi-channnel radiometer,

transmission line. Considering the integral structure, E-plane and H-plane transitions

have been designed respectively, which are integrated in a module by back-to-back

structure. The measured results of the back-to-back structure (a 6.6mm long coplanar

waveguide transmission line included) show that, in the whole V-band, the reflection

coefficient is better than -13dB, and the insertion loss is better than 1.1dB.

The division of different channels of the radiometer front-end can be realized by

using separate network. A magic-T with filters embedded in each output arms or a

splitter can be employed in the separate network according to the band overlap exists or

not between the two desired separate channels, respectively. For the desired 50 to 60

GHz frequency band, a broadband magic-T is simulated. The simulated results show

A V-band Single-Pole Single-Throw (SPST) switch is designed for the

ABSTRACT

noise-injection module which is for calibration. A simplified physical model of the PIN

diode is created in HFSS. And by extracting the parameters again and again, the

insertion loss of the designed SPST switch is below 1dB, and the isolation is beyond

16dB in the 50 to 65GHz frequency band.

The detector changes high frequency signals into low ones which are convenient to

deal with by the back-end. It is a key module in the radiometer front-end. Through

building a simplified physical model of the detector diode and designing broadband

DC-loop, Low-Pass-Filter (LPF) and matching circuit, the voltage sensitivity of the

designed zero-biased detector is beyond 4800mV/mW in the 50 to 60GHz frequency

目录

目 录

第一章 绪 论 .................................................................................................................. 1

1.1 微波辐射计简介 ............................................................................................... 1

1.2 微波辐射计前端关键技术的国内外研究进展 ............................................... 2

1.3 论文的主要研究工作 ........................................................................................ 6

第二章 V 波段波导到共面波导宽带过渡研制 ............................................................ 8

2.3 过渡结构实物加工及测试 ............................................................................. 14

2.4 本章小结 ......................................................................................................... 15

第三章 V 波段宽带魔 T 和分路器研究 ...................................................................... 16

3.1 V 波段宽带魔 T ............................................................................................... 16

3.2 V 波段分路器 .................................................................................................. 19

4.5 低通滤波器设计 ............................................................................................. 28

目录

4.6 整体电路仿真设计 ......................................................................................... 29

4.7 实物加工测试及结果分析 ............................................................................. 31

4.8 本章小结 ......................................................................................................... 34

第五章 V 波段宽带检波器研制 .................................................................................. 35

5.1 检波器基本理论 ............................................................................................. 35

5.7 本章小结 ......................................................................................................... 47

第六章 总结与展望 ...................................................................................................... 48

致 谢 .............................................................................................................................. 49

参考文献 ........................................................................................................................ 50

攻读硕士学位期间取得的成果 .................................................................................... 52