【作者】 宁俊松；

【导师】 罗正祥；

【作者基本信息】 电子科技大学 ， 物理电子学， 2009， 博士

【摘要】 高温超导薄膜（HTS）在微波频段下，具有极为优越的微波性能：在L、S波段其微波表面电阻R_s比常规金属导体的要低3～5个数量级，并能够实现高达1×10⁷A／cm²的电流密度。利用这些高温超导薄膜已经制造出许多高温超导无源微波器件（如滤波器、多工器、功分器、限幅器、延迟线等）与电路（如放大器、振荡器、高速A／D转换器等），它们具有比常规器件和电路更高的性能，这些高性能的高温超导无源微波器件与电路，应用到现代移动通信系统、卫星通信系统、雷达系统以及电子战（EW）侦察接收机系统中，将极大的提升系统性能，具有十分广阔的应用前景。本论文主要工作内容：设计和研制高灵敏高温超导接收机前端的关键器件—高温超导滤波器和多工器，并与数字接收机技术相结合，研制开发新型宽带数字接收机的高灵敏高温超导双通道前端样机。虽然现在高温超导微波器件的设计是基于传统的常规微波器件的设计技术，但是由于高温超导技术的应用有些限制性的条件以及自身的特点，传统的常规滤波器和多工器设计需要进行一些发展改进以适合高温超导技术的应用。找到一种适合高温超导滤波器和多工器的简便、快速、准确的设计方法是我们研究的重点，并在此基础上开发研制新型宽带数字接收机的高性能高温超导多通道前端系统。本论文主要创新性工作如下：1、发展了一种快速、准确的滤波器CAD设计方法：利用滤波器的谐振器与其频率响应的对应关系，结合计算机强大仿真能力，来完成滤波器的设计。设计过程不再需要优化过程，大大节省了结构较复杂、级数较多的高温超导滤波器的设计周期，并通过实验验证了这个设计方法。制作的8级高温超导滤波器和低温工作低噪声放大器组件，工作频段XXX-XXXMHz，通带带宽5MHz，在77K下测试结果：带内增益21dB左右；带内反射小于-12dB；带内噪声小于0．8dB，最小噪声0．58dB。（论文第二章）2、针对设计过程更为复杂、困难的高温超导多工器的设计，发展了直接设计法设计高温超导多工器。通过对多工器的集总参数电路模型的研究，找到影响多工器性能的主要参数以及其调整变化的趋势，以获得较理想的初值，节省优化时间，避免复杂的理论和冗长的公式演算，并通过实验验证了这个设计方法。制作的四级高温超导双工器工作在3-4GHz频段，通道带宽500MHz，在温度77K下测试，测试结果达到：通带内插损小于0．8dB，通带间带外抑制大于30dB@通带中心频率，通带内反射小于-10dB；制作的四级高温超导四工器工作在2-4GHz频段，通道带宽500MHz，在温度77K下测试，测试结果达到：通带内插损小于0．8dB，通带间带外抑制大于30dB@通带中心频率，通带内反射在-10dB左右。（论文第三章）3、开展了高温超导多工器功率容载能力的研究。通过实验发现高温超导连续通带多工器在其交接区域内的功率容载能力并不比其单个通道带内的功率容载能力高，反而要低1dB左右。原因是高温超导连续通带多工器交接区域存在着大量微波电流，这些微波电流增加了多工器在交接区域内的损耗，因而降低了其交接区域内功率容载能力。（论文第三章）4、研制开发了宽带数字接收机的高灵敏高温超导双通道前端样机。实验测试样机在频段XXX-XXXGHz，中频带宽为500MHz，各通道灵敏度S在-85dBm和-86dBm之间，换算成系统总噪声系数N_F在1．0dB和1．3dB之间；输出功率1dB压缩点P_1dB=15．7dBm，输出功率三阶交截点OIP3=27．7dBm，系统总增益G=47．8dB（论文第四章）更多还原

【Abstract】 The high temperature superconducting (HTS) is a preferable microwave device material due to its three or five orders lower surface impedance than those of normal metals at L to X band and its large current density which can reach to 1×10~7 A/cm~2. Many low insertion loss HTS devices have been produced in recent years, including HTS filters, HTS multiplexers, HTS limiters, HTS delay lines, etc. When these high-performance HTS devices are used in the microwave systems ~ including mobile communication systems, Satellite communication systems, radar systems and electronic warfare receiver systems, these systems’ performance has been greatly enhanced, which shows a great prospect of application.Though the design of HTS multiplexer is based on that of conventional multiplexer, the design procedures have to be modified due to some limited conditions when the HTS technology is in application. In this thesis, we developed the designs of HTS contiguous diplexers and HTS contiguous quadraplexers which are the key devices of the HTS receiver front-end. Experiments have been done to validate the design concept which is applied to the research and development of a new multi-channel HTS front-end in wideband digital receiver systems. The fabricated prototype of double-channel HTS front-end shows a high performance.The main results are as follows:1. We have developed the design of HTS filters, which are based on the relations between the parameters of filters’ resonators and the frequency response of filters. The developed design procedures can reach to the design object more quickly and accurately without optimization process by the powerful computer simulation, which significantly reduces the designning period of HTS filters. Experiments have been done to validate the design concept. The fabricated 8-pole HTS filter and LNA modules operated at 77 K, and their performance of xxx-xxx MHz with 5 MHz wide is as follows: gain>21dB and noise figure<0.8dB.2. For the more complex and difficult design of HTS multiplexers, we have developed a "direct designing": The LC lumped parameter models of multiplexers are used for the analysis of the relations between the parameters of lumped parameter models and the frequency response of multiplexers. In this way we can know the main parameters that affect the performance of multiplexers and the trend to get an ideal matching. Thus, we can efficiently simplify the design task and significantly reduces amount of optimization time. Experiments have been done to validate the design concept. The fabricated 4-pole HTS diplexer and 4-pole HTS quadraplexer operated at 77 K shows excellent performance which operation frequency was from 3GHz to 4GHz with 500-MHz-wide channels and from 2GHz to 4GHz with 500-MHz-wide channels respectively. The insertion loss in the pass-band is less than 0.8 dB and the rejection between per channel is greater than 30dB.3. The power handling properties of a HTS diplexer have been measured. The tested power dependent frequency response of the HTS diplexer shows that the power handling capability of the HTS diplexer on the crossover region is not higher than that on the in-band region, even somewhat lower 1dB, due to larger microwave currents in the device in the crossover region.4. We have developed the technology of a new muli-channel HTS front-end in wideband digital receiver systems. The fabricated prototype of double-channel HTS front-end shows a high performance. Their performance of each channel is as follows: noise figure< 1.3 dB, P1dB=15.7dBm, OIP3=27.7dBm, G=47.8dB and S<-85dBm, when its operation frequency was from xxx GHz to xxx GHz with 500-MHz-wide channels.更多还原