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[IEEE 2018 International Conference on Microwave and Millimeter Wave Technology (ICMMT) - Chengdu, China (2018.5.7-2018.5.11)] 2018 International Conference on Microwave and Millimeter Wave Technology (ICMMT) - Detection of Uniformly Accelerated Spinning Target Based on OAM Beams
摘要： In recent years, it has been validated that electromagnetic (EM) wave carrying orbital angular momentum (OAM) can be exploited to detect the angular velocity of spinning targets with uniform velocity. In this paper, the detection method of uniformly accelerated spinning target using OAM beams is studied. The time-frequency analysis approaches, including the Wigner-Ville distribution (WVD) and the fractional order Fourier transform (FRFT), are used to analyze the rotational Doppler frequency shift caused by spinning targets. Simulation results indicate that the resolution of acceleration is dependent on the spectrum width of time-frequency diagrams of the echo signal.
关键词： OAM beams,rotational Doppler frequency shift,uniformly accelerated spinning target,Wigner-Ville distribution,fractional order Fourier transform
更新于2025-09-23 15:22:29
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[IEEE SoutheastCon 2018 - St. Petersburg, FL (2018.4.19-2018.4.22)] SoutheastCon 2018 - An Examination of Dichotomous and Centroid Tracking of a Monopulse Angle Tracking Unit
摘要： The engineering community is confident in its assessment of how an angle tracker will perform in a multi-target environment as the target-to-tracker range decreases, causing targets to leave the tracker antenna beam. When one target signal dominates due to the angular separation of the targets, the tracker will center on the dominating signal. It is not well understood how the tracker will behave when angle separation is not the limiting factor in signal strength. That topic is addressed in this paper. Specifically, we show how angle error signal normalization impacts track loop dynamics in a dual target scenario. If the error signal is normalized by an Automatic Gain Control (AGC), the behavior will depend upon the Doppler frequency separation of the two targets relative to the AGC bandwidth. The problem is addressed from a theoretical perspective, and via simulation. The theoretical and simulation results agree well.
关键词： simulation,AGC,angle tracker,Automatic Gain Control,Doppler frequency,monopulse
更新于2025-09-23 15:21:01
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Broadband Laser Doppler Frequency Shift Emulator for Satellite Laser Communication
摘要： A novel emulator of laser Doppler frequency shift (DFS) for satellite laser communication based on microwave photonics technology is proposed and experimentally demonstrated. In order to overcome the bottleneck that the optical frequency shift signal with a wide frequency offset from near zero can hardly be obtained using traditional electro-optic or acousto-optic frequency shifting, the frequency of laser signal is first moved to a lower/higher fixed frequency and then shifted back to a higher/lower tunable frequency. The signal after cascaded frequency shifting in the opposite direction is equivalent to the original laser signal with DFS. In the experiment, the value and direction of DFS correspond to the magnitude and sign of the difference between the two frequency shifts. The DFS from -14GHz to +14GHz with a varying rate of 323MHz/s is accurately implemented. In addition, the side mode suppression ratio (SMSR) of laser signals with DFS are all over 52.3dB. The proposed scheme is significant to evaluate and test the DFS compensation capability of the satellite laser communication terminal.
关键词： Doppler Frequency Shift,Satellite laser communication,Electro-optic cascaded frequency shifting
更新于2025-09-12 10:27:22
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[IEEE 2019 14th IEEE Conference on Industrial Electronics and Applications (ICIEA) - Xi'an, China (2019.6.19-2019.6.21)] 2019 14th IEEE Conference on Industrial Electronics and Applications (ICIEA) - Channel Tracking and Hybrid Energy Beamforming for WPT Enabled IoT System with Mobile mMIMO BS
摘要： In this paper, we consider the channel tracking and energy hybrid beamforming for the wireless power transfer (WPT) enabled Internet of Things (IoT) system, where the mobile base station (MBS) serves a set of half-duplex (HD) sensors that are uniformly distributed within its coverage area. A linear Kalman filter based multipath channel tracking and hybrid energy beamforming scheme is proposed by investigating the temporal and spatial properties of channel. Firstly, the Doppler frequency offset (DFO) is compensated through beam alignment and capturing the precise angular information from signals. Then, the multipath channel is tracked during the angle of arrival time (AOAT). Finally, the hybrid beamforming is applied to realize downlink WPT and uplink data transmission. The superiority of the proposed scheme is evaluated through simulations.
关键词： angle of arrival time (AOAT),mobile base station (MBS),wireless power transfer (WPT),hybrid energy beamforming,Kalman filter,Internet of Things (IoT),Channel tracking,Doppler frequency offset (DFO)
更新于2025-09-11 14:15:04
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Analytical Solution of Direct and Inverse Problems in the Internal Gravity Waves Studies by the Doppler Frequency Shift Method
摘要： An analytical solution of direct and inverse problems arising in the study of the internal gravity waves (IGWs) dynamic via recording of the Doppler frequency shift, is presented. The direct problem is to determine the response of the Doppler shift to IGWs in the region of the radio wave reflection point; the inverse problem is the determination of IGW parameters from data on the Doppler frequency shift. Solutions were obtained in an approximation of the isothermal ionosphere for the heights of the F-region. They are presented in a form convenient for their practical use and can have a wide range of applications, including the detection of soliton-like wave structures in the F-region of the ionosphere.
关键词： inverse problem,ionosphere,direct problem,internal gravity waves,Doppler frequency shift
更新于2025-09-09 09:28:46