- 标题
- 摘要
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- 实验方案
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Dual-Layer Single-Varactor Driven Reflectarray Cell for Broad-Band Beam-Steering and Frequency Tunable Applications
摘要： A dual-layer active reflectarray configuration is proposed for broad-band beam-steering and/or frequency-tunable applications. A unit cell composed by two stacked fixed-size rectangular patches, properly loaded with a single varactor diode, is designed to realize the dynamic phase tuning mechanism. The proposed approach offers wider bandwidths, with respect to the existing varactor-based reflectarray cells, and quite good frequency reconfigurability features, as demanded by several radar or satellite communication applications. An X-band reflectarray cell is fabricated and tested, to prove the effectiveness of the proposed approach, achieving a 318° phase agility within a measured frequency range of about 14.6% with respect to the central design frequency (i.e., 11 GHz). Wideband beam-steering reflectarray designs are demonstrated, showing 1-dB gain bandwidths equal to 9–10%.
关键词： varactor,wideband,Reflectarray,beam-steering
更新于2025-09-23 15:23:52
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[IEEE 2018 IEEE International Conference on RFID Technology & Application (RFID-TA) - Macau, Macao (2018.9.26-2018.9.28)] 2018 IEEE International Conference on RFID Technology & Application (RFID-TA) - Polarization Reconfigurable Antenna with Beam Steering Performance
摘要： This paper proposed a novel method reconfiguring the polarization of the dielectric resonator antenna (DRA) with beam steering performance. During the process of liquid alteration between the two zones of the 3-D printed container, the proposed antenna performed with beam steering performance. What's more, the polarization was switched with the beam steering process. The proposed design is suitable for the application as a RFID reader.
关键词： dielectric resonator antenna,Radio frequency identification (RFID),polarization reconfigurable,beam steering
更新于2025-09-23 15:22:29
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Ultrathin Microwave Devices for Polarization-Dependent Wavefront Shaping Based on an Anisotropic Metasurface
摘要： Metasurfaces have recently become a promising material, offering new degrees of freedom in molding electromagnetic wave properties. In this work, we propose and numerically investigate ultrathin microwave devices for polarization-dependent wavefront shaping based on an anisotropic metasurface, which consists of a square metal ring with a cross, a dielectric substrate, and a metal ground plane. It is demonstrated the proposed metasurface can independently manipulate reflective x- and y-polarized wavefronts at frequency of 15 GHz via engineering of the metal cross. Furthermore, the reflective efficient is extremely high, reaching a near-unity value of 0.98. Based on this anisotropic metasurface, a polarization beam splitter is achieved by artificially arranging the spatial distribution of metasurfaces with prescribed geometries. In addition, we successfully design a focusing metasurface to separate the x- and y-polarized beams via focusing them at different positions. The proposed approach paves a way toward the applications of the metasurface in a microwave band.
关键词： electromagnetic metamaterials,microwave propagation,beam steering,microwave antennas
更新于2025-09-23 15:22:29
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A Versatile Silicon-Silicon Nitride Photonics Platform for Enhanced Functionalities and Applications
摘要： Silicon photonics is one of the most prominent technology platforms for integrated photonics and can support a wide variety of applications. As we move towards a mature industrial core technology, we present the integration of silicon nitride (SiN) material to extend the capabilities of our silicon photonics platform. Depending on the application being targeted, we have developed several integration strategies for the incorporation of SiN. We present these processes, as well as key components for dedicated applications. In particular, we present the use of SiN for athermal multiplexing in optical transceivers for datacom applications, the nonlinear generation of frequency combs in SiN micro-resonators for ultra-high data rate transmission, spectroscopy or metrology applications and the use of SiN to realize optical phased arrays in the 800–1000 nm wavelength range for Light Detection And Ranging (LIDAR) applications. These functionalities are demonstrated using a 200 mm complementary metal-oxide-semiconductor (CMOS)-compatible pilot line, showing the versatility and scalability of the Si-SiN platform.
关键词： transceiver,silicon photonics,Kerr nonlinearity,optical phased array,Coarse Wavelength Division Multiplexing (CWDM),multiplexing,LIDAR,silicon nitride,beam steering,frequency comb,grating coupler
更新于2025-09-23 15:22:29
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Experimental Evaluation of Multipath Mitigation in TDOA-Based Indoor Passive Localization System Using A Beam Steering Broadband Circular Polarization Antenna
摘要： An experimental evaluation of multipath mitigation using a beam steering broadband circular polarization antenna (BSBCPA) in indoor passive localization system based on time differences of arrival (TDOA) is presented in this paper. The BSBCPA consists of a beam switch network, four identical hexagon patch elements and their respective feeding networks. By controlling the states of a radio frequency (RF) switch in the beam switch network, four steering circular polarization beams can be excited separately for azimuth omnidirectional coverage. Combining the spatial selectivity of steering beams and circular polarization in the BSBCPA, the positioning inaccuracy from indoor multipath propagation can be mitigated. In two different indoor environments with line of sight (LOS), complex multipath, when transmitting a 20 MHz bandwidth signal in WLAN, the 2D positioning mean error obtained is 0.7 m and 0.82 m, respectively. Compared with conventional omnidirectional linear polarization antenna (OLPA), the BSBCPA can at least improve positioning accuracy by 51%. The experimental results show that the proposed BSBCPA can significantly mitigate multipath propagation for TDOA-based indoor passive localization.
关键词： multipath mitigation,beam steering antenna,indoor passive localization,circular polarization,TDOA
更新于2025-09-23 15:22:29
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Decoupling Beam Steering and User Selection for MU-MIMO 60-GHz WLANs
摘要： Multi-user transmission at 60 GHz promises to increase the throughput of next-generation WLANs via both analog and digital beamforming. To maximize the capacity, analog beams need to be jointly configured with user selection and digital weights; however, joint maximization requires prohibitively large training and feedback overhead. In this paper, we scale multi-user 60-GHz WLAN throughput via design of a low-complexity structure for decoupling beam steering and user selection such that analog beam training precedes user selection. We introduce a two-class framework comprising: 1) single-shot selection of users by minimizing overlap of their idealized beam patterns obtained from analog training and 2) interference-aware incremental addition of users via sequential training to better predict inter-user interference. We implement a programmable testbed using software-defined radios and commercial 60-GHz transceivers and conduct over-the-air measurements to collect channel traces for different indoor WLAN deployments. Measurements are conducted using a 12-element phased antenna array as well as horn antennas with different directivity gains to evaluate the performance of practical 60-GHz systems. Using trace-based emulations and high resolution 60-GHz channel models, we show that our decoupling structure experiences less than 5% performance loss compared with maximum achievable rates via joint user-beam selection.
关键词： user selection,MU-MIMO,digital beamforming,60 GHz,IEEE 802.11ay,beam steering
更新于2025-09-23 15:21:21
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IEEE Access Special Section Editorial: Optical Wireless Technologies for 5G Communications and Beyond
摘要： Wide bandwidth and dense spatial reuse are of extreme importance for future wireless communication networks, including 5G and beyond. In particular, these properties are important to enable future wireless networks to cope with the explosive increase in the demand for high data-rate communications. Optical wireless communications (OWC) is a promising technology for achieving this goal due to the abundant reusable license-free optical spectrum. This potential of OWC attracted significant global attention both from communications and optoelectronics viewpoints, and continues to do so.
关键词： 5G,beam-steering,mixed FSO/fiber backhauling,OFDM,MIMO,Optical wireless communications,vehicle-to-vehicle communications,free-space optics,vehicle-to-infrastructure communications,network-layer aspects,visible-light communications
更新于2025-09-23 15:21:21
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SURVEY OF BEAM STEERING TECHNIQUES AVAILABLE FOR MILLIMETER WAVE APPLICATIONS
摘要： Pattern reconfigurable antennas (beam steerable antennas) are essential for various applications in electronic engineering such as telecommunication and radar. They mitigate interference by channelling the antenna’s radiation to the direction of interest. This ability is vital for millimetre wave frequency applications such as small cell backhaul links where high path loss, attenuation from obstacles, and misalignment due to wind sway and accidents are prevalent. Several techniques have been used to implement beam steering over the years, most of which achieves steering at the expense of antenna performance. In this article, we surveyed the various techniques used in achieving beam steering and analyse each based on some figures of merit with the aim of identifying areas of improvements for each beam steering technique.
关键词： radar,pattern reconfigurable antennas,beam steering,telecommunication,millimetre wave
更新于2025-09-23 15:21:21
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Coherent control of spatial and angular Goos-H?¤nchen shifts in a metal-clad waveguide structure
摘要： A metal-clad waveguide backed by a coherent atomic medium is proposed to achieve tunable giant spatial and angular Goos-H?nchen (GH) shifts. With a metal layer of appropriate thickness, a large GH shift can occur simultaneously for transverse-magnetic- and transverse-electric-polarized light beams when the waveguide modes are resonantly excited. The phase change and dip slope of the re?ection coef?cient around the resonance angle are closely related to the system’s internal damping, which depends on the absorption of the medium. Then based on the quantum coherence effect, the spatial and angular shifts can be greatly enhanced by adjusting the parameters of the atomic system. The lateral displacement can also be switched from positive to negative or vice versa via coherent control of the absorption by the medium. Moreover, the dependence of the resonance angle of the guided mode on the refractive index makes the peak position of GH shifts tunable. The proposed scheme provides more ?exibility for manipulating the spatial and the angular GH shifts, and it has potential applications in optical switches, beam steering, etc.
关键词： optical switches,coherent atomic medium,quantum coherence effect,beam steering,Goos-H?nchen shifts,metal-clad waveguide
更新于2025-09-23 15:21:01
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Beam Steering of a Terahertz Semi Bow Tie Antenna Using Parasitic Graphene Ribbons
摘要： In this paper, a reconfigurable beam-scanning planar antenna is proposed in terahertz frequencies. The presented structure consists of a semi bow tie antenna surrounded by circularly arranged parasitic pieces of graphene. The performance of the proposed antenna is investigated considering three different states where a PEC ground plane and a graphene ground layer with chemical potentials 0 (mode A) and 1 (mode B) are utilized at the bottom of the substrate. The proposed antenna is designed for utilization at a specific frequency of 1.2 THz in all these three states. The achieved antenna boresight and radiation pattern are altered through changing the conductivity of parasitic graphene elements and ground plane, which is obtained by controlling the corresponding chemical potential of the graphene segments. In addition, the parasitic graphene elements, located around the antenna, provide a high degree of freedom for altering the radiation pattern and antenna boresight. The parasitic elements operate as directors in modes A and B, whereas they act as reflectors in PEC ground state. Moreover, a high beam steering capability is obtained as chemical potentials of graphene elements are allocated between 0 and 1, whereas a PEC ground layer is employed at the bottom of the antenna. It should be noted that the gain and front-to-back ratio of the antenna are controlled using different chemical potentials of the graphene elements. A wide range of scan angles allocated between 0 and 180°, and toward the left and right directions in constant φ plane is achieved for the designed antenna.
关键词： Terahertz,Graphene,Reconfigurable,Beam steering,Antenna
更新于2025-09-23 15:21:01