This paper introduces a compact dual notched UWB antenna with an independently controllable WLAN notched band integrated with fixed WiMAX band-notch.The proposed antenna utilizes a slot resonator placed in the main ra...This paper introduces a compact dual notched UWB antenna with an independently controllable WLAN notched band integrated with fixed WiMAX band-notch.The proposed antenna utilizes a slot resonator placed in the main radiator of the antenna for fixed WiMAX band notch,while an inverted L-shaped resonator in the partial ground plane for achieving frequency agility within WLAN notched band.The inverted L-shaped resonator is also loaded with fixed and variable capacitors to control and adjust the WLAN notch.The WLAN notched band can be controlled independently with a wide range of tunability without disturbing the WiMAX bandnotch performance.Step by step design approach of the proposed antenna is discussed and the corresponding mathematical analysis of the proposed resonators are provided in both cases.Simulation of the proposed antenna is performed utilizing commercially available 3D-EM simulator,Ansoft High Frequency Structure Simulator(HFSS).The proposed antenna has high selectivity with experimental validation in terms of reflection coefficient,radiation characteristics,antenna gain,and percentage radiation efficiency.The corresponding measured frequency response of the input port corresponds quite well with the calculations and simulations in both cases.The proposed antenna is advantageous and can adjust according to the device requirements and be one of the attractive candidates for overlay cognitive radio UWB applications and URLLC service in 5G tactile internet.The proposed multifunctional antenna can also be used for wireless vital signs monitoring,sensing applications,and microwave imaging techniques.展开更多
High-frequency resonance can occur when a modular multilevel converter(MMC)is inserted into an AC grid.Additional damping control is a relatively low-cost resonance suppression strategy compared to passive damping str...High-frequency resonance can occur when a modular multilevel converter(MMC)is inserted into an AC grid.Additional damping control is a relatively low-cost resonance suppression strategy compared to passive damping strategies.This paper analyzes the influences of a feed-forward voltage filter and feedback current filter for the inner controller for the high-frequency impedance characteristics of the MMC based on a model.Moreover,the mechanism,influencing factors,and limitations of the existing strategy including an additional lowpass filter in the voltage feed-forward stage are investigated.Secondly,a resonance suppression strategy for the inclusion of additional cascaded notch filters in the voltage feed-forward stage is proposed,and its parameter design method and applicable scenarios are analyzed.In addition,this paper analyzes the effects of the inclusion of an additional control in other stages for the inner controller of the MMC.Finally,the correctness of the theoretical analysis and the proposed strategy is verified based on the simulation of an actual project on PSCAD/EMTDC.展开更多
A novel equilateral triangular patch with a rectangular notch etched to one radiating edge on organic magnetic substrate is proposed for dual frequency operation. Both operations of these dual frequencies arise from t...A novel equilateral triangular patch with a rectangular notch etched to one radiating edge on organic magnetic substrate is proposed for dual frequency operation. Both operations of these dual frequencies arise from the perturbation of TM 10 and TM 11 mode by simply cutting a rectangular notch at the patch bottom. Simulations and experiments have shown the validity of this design. Using an organic magnetic material as the substrate, the antenna exhibits a broader bandwidth of 5.5% and 4.7% at dual-frequencies 1.56 GHz and 2.45 GHz, respectively, as well as a reduced size compared to the dual-frequency patch antennas on non-magnetic material.展开更多
分析了激光捷联惯性导航系统中的激光陀螺频谱特性,指出激光捷联惯性导航系统中三个激光陀螺的抖动频率会互相干扰。提出一种多凹点有限冲击响应低通滤波器频域设计方法,通过指定三个抖动频率点幅值为小量,在幅频特性曲线上产生三个凹...分析了激光捷联惯性导航系统中的激光陀螺频谱特性,指出激光捷联惯性导航系统中三个激光陀螺的抖动频率会互相干扰。提出一种多凹点有限冲击响应低通滤波器频域设计方法,通过指定三个抖动频率点幅值为小量,在幅频特性曲线上产生三个凹陷点。该滤波器采用标准滤波算法,同时实现了对激光捷联惯性导航系统三个激光陀螺的滤波和机抖信号的陷波。给出了一个24阶多凹点滤波器设计实例,幅频特性分析说明,由于三个陷波点的集中,该滤波器还可以在机抖频率可能存在的频段上,提供额外的80 d B以上的衰减,可防止激光陀螺抖动频率漂移后陷波性能下降。试验结果表明,多凹点滤波器输出数据波动幅度比原激光捷联惯性导航系统使用的滤波器结果减小5~8倍,三轴摇摆试验的导航精度也有一定提高。展开更多
文摘采用加载谐振器结构,设计了一款在8 GHz处具有陷波特性的超宽带滤波器,有效地避免了X波段卫星通信系统(7.9~8.395 GHz)的连续波对超宽带通信系统的干扰。在三模谐振器的基础上加载中心加载谐振器,通过调整加载谐振器的参数对陷波频率进行调控,使得滤波器在超宽带范围内产生陷波。利用HFSS进行仿真后结果表明,该超宽带滤波器的通带在2.5~10.3 GHz,通带范围内插入损耗在0.9 d B左右,带外衰减十分陡峭。其陷波中心频率发生在8.19 GHz,在陷波频段(7.98~8.40 GHz)范围内最小插入损耗低于–7 d B,具有良好的抑制水平,整体性能表现优良。实际测试结果与仿真结果基本一致,性能指标能够达到设计要求。
基金supported by the National Research Foundation of Korea(NRF)grant funded by the Korean government(MSIT)(No.2019R1A4A1023746,No.2019R1F1A1060799)the Strengthening R&D Capability Program of Sejong University.
文摘This paper introduces a compact dual notched UWB antenna with an independently controllable WLAN notched band integrated with fixed WiMAX band-notch.The proposed antenna utilizes a slot resonator placed in the main radiator of the antenna for fixed WiMAX band notch,while an inverted L-shaped resonator in the partial ground plane for achieving frequency agility within WLAN notched band.The inverted L-shaped resonator is also loaded with fixed and variable capacitors to control and adjust the WLAN notch.The WLAN notched band can be controlled independently with a wide range of tunability without disturbing the WiMAX bandnotch performance.Step by step design approach of the proposed antenna is discussed and the corresponding mathematical analysis of the proposed resonators are provided in both cases.Simulation of the proposed antenna is performed utilizing commercially available 3D-EM simulator,Ansoft High Frequency Structure Simulator(HFSS).The proposed antenna has high selectivity with experimental validation in terms of reflection coefficient,radiation characteristics,antenna gain,and percentage radiation efficiency.The corresponding measured frequency response of the input port corresponds quite well with the calculations and simulations in both cases.The proposed antenna is advantageous and can adjust according to the device requirements and be one of the attractive candidates for overlay cognitive radio UWB applications and URLLC service in 5G tactile internet.The proposed multifunctional antenna can also be used for wireless vital signs monitoring,sensing applications,and microwave imaging techniques.
基金supported in part by Science and Technology Project of State Grid Corporation of China,“Research on Harmonic Oscillation ProblemsSuppression Strategies of Flexible DC Connected to AC Grid”,(No.SGTYHT/17-JS-199).
文摘High-frequency resonance can occur when a modular multilevel converter(MMC)is inserted into an AC grid.Additional damping control is a relatively low-cost resonance suppression strategy compared to passive damping strategies.This paper analyzes the influences of a feed-forward voltage filter and feedback current filter for the inner controller for the high-frequency impedance characteristics of the MMC based on a model.Moreover,the mechanism,influencing factors,and limitations of the existing strategy including an additional lowpass filter in the voltage feed-forward stage are investigated.Secondly,a resonance suppression strategy for the inclusion of additional cascaded notch filters in the voltage feed-forward stage is proposed,and its parameter design method and applicable scenarios are analyzed.In addition,this paper analyzes the effects of the inclusion of an additional control in other stages for the inner controller of the MMC.Finally,the correctness of the theoretical analysis and the proposed strategy is verified based on the simulation of an actual project on PSCAD/EMTDC.
文摘A novel equilateral triangular patch with a rectangular notch etched to one radiating edge on organic magnetic substrate is proposed for dual frequency operation. Both operations of these dual frequencies arise from the perturbation of TM 10 and TM 11 mode by simply cutting a rectangular notch at the patch bottom. Simulations and experiments have shown the validity of this design. Using an organic magnetic material as the substrate, the antenna exhibits a broader bandwidth of 5.5% and 4.7% at dual-frequencies 1.56 GHz and 2.45 GHz, respectively, as well as a reduced size compared to the dual-frequency patch antennas on non-magnetic material.
文摘分析了激光捷联惯性导航系统中的激光陀螺频谱特性,指出激光捷联惯性导航系统中三个激光陀螺的抖动频率会互相干扰。提出一种多凹点有限冲击响应低通滤波器频域设计方法,通过指定三个抖动频率点幅值为小量,在幅频特性曲线上产生三个凹陷点。该滤波器采用标准滤波算法,同时实现了对激光捷联惯性导航系统三个激光陀螺的滤波和机抖信号的陷波。给出了一个24阶多凹点滤波器设计实例,幅频特性分析说明,由于三个陷波点的集中,该滤波器还可以在机抖频率可能存在的频段上,提供额外的80 d B以上的衰减,可防止激光陀螺抖动频率漂移后陷波性能下降。试验结果表明,多凹点滤波器输出数据波动幅度比原激光捷联惯性导航系统使用的滤波器结果减小5~8倍,三轴摇摆试验的导航精度也有一定提高。
