【作者】 王正；

【导师】 殷晓星；

【作者基本信息】 东南大学 ， 电磁场与微波技术， 2023， 硕士

【摘要】 随着无线通信技术的不断发展,通信设备越来越多,外部电磁环境也日益复杂,对应用系统的电磁兼容性的要求越来越高。本文研究了用于提高设备电磁兼容性的天线和滤波器。在陷波天线、共模滤波器和天线解耦三个应用领域中,本文的主要工作如下:1.提出并实现了一种基于开口谐振环阵列的超宽带无反射式陷波天线,使用该天线,可以减少设备对外界的电磁干扰。该天线利用开口谐振环的金属损耗和基板的介质损耗,实现了不加载电阻的无反射式吸收阵列。实测和仿真结果一致,显示该天线的阻带带宽为2～10 GHz,其中陷波带宽为5～6 GHz的陷波天线;在陷波频段中,电磁能量最大吸收效率可达到95%,天线的可实现增益降低超过了10 d B。2.提出并实现了一种应用于高速数字电路的共模抑制滤波器。该滤波器采用了两种相互耦合的缺陷地结构。建立了奇偶模等效电路,分析其产生共模阻带的物理机理和传输零点,为后续的改进和优化提供了依据。同时设计实现了基于耦合微带线和耦合带状线的两种共模滤波器,两者实测与仿真结果基本吻合,其中前者的共模阻带为1～8.9 GHz,相对共模阻带宽159%,后者的共模阻带为1.1～10 GHz,相对共模阻带宽160%。3.设计了用于天线去耦的对消结构。该结构基于差模和共模的不同特性,通过调节金属地平面的大小和加载槽线结构,使得二端口天线系统的差模反射系数和共模反射系数相等,在没有额外的去耦结构情况下,天线阵有着良好的自去耦性能。设计实现了用于对消去耦天线的一款超宽带巴伦。该巴伦实测和仿真结果一致,显示在工作频段2.1～9.25 GHz内,幅度不平衡度和相位不平衡度分别在0.5 d B之内和-2°～6.7°之间,幅相平衡性能优良。综上所述,本文在三个应用领域中提出的设计方法可以有效提高设备的电磁兼容性,在相关领域中有着较好的应用前景。更多还原

【Abstract】 With the developments of wireless communication technology,more communication devices take an increasingly complex external electromagnetic environment,and the requirements for the electromagnetic compatibility of application systems are becoming higher.This paper researches on the antennas and filters for improving the electromagnetic compatibility of equipment.The work in this paper is in three application areas,namely bandnotched antennas,common-mode filters and antenna decoupling,respectively,as follows:(1)A band-notched ultrawideband antenna with a reflectionless feature based on split-ring resonator arrays is proposed and implemented to reduce electromagnetic interference from devices to the environment.By using the metal loss of split-ring resonators and the dielectric loss of dielectric substrate,a reflectionless absorption array without loading resistors is designed.The measured and simulated results are consistent and show that the antenna has an impedance bandwidth of 2～10 GHz and notched frequency band at 5～6 GHz.At notched frequency band,nearly 95% reflected energy is dissipated in dielectric and conductor,and the realized gain drops over 10 d B.(2)A common-mode filter applied in high-speed digital circuits is proposed and implemented.The filter employs two mutually coupled defected ground structures.To give a physical insight of CM noise suppression and derive CM transmission zeros,the odd-even mode equivalent circuit models are established and analyzed,which provide a basis for subsequent improvements and optimisations.Two common-mode filters based on coupled microstrip lines and coupled strip lines are designed and implemented,and the measured results are similar with simulated results.The former has a frequency band from 1 to 8.9 GHz for CM noise suppression,with a relative CM noise suppression bandwidth of 159%,while the latter has a frequency band from 1.1 to 10 GHz for CM noise suppression,with a relative commonmode resistance bandwidth of 160%.(3)The design of a decoupling structure for antenna decoupling is proposed.The structure is based on the different characteristics of differential modes and common modes.By adjusting the size of the ground and loading slot line structure,the reflection coefficient of CM and DM of two-port antenna system are equal,and the antenna array has good self-decoupling performance without using any extra decoupling structure.An ultra-wideband balun is designed and implemented for the decoupling antennas.The measured and simulated results are consistent and show that the amplitude and phase imbalance are within 0.5 d B and-2° ～ 6.7°respectively in the operating band 2.1～9.25 GHz,with excellent amplitude and phase balance performance.In summary,the design method proposed in this paper can effectively improve the electromagnetic compatibility of the devices in the three application areas,and has potential applications in microwave field.更多还原