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- 实验方案
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[IEEE 2018 International Conference on Current Trends towards Converging Technologies (ICCTCT) - Coimbatore (2018.3.1-2018.3.3)] 2018 International Conference on Current Trends towards Converging Technologies (ICCTCT) - Broadband Circularly Polarized U-Slot Antenna for Wireless Application
摘要： The antenna presented in this paper is a broadband circularly polarized U slot antenna. The circularly polarized radiation is achieved in this paper by suspending two separated rectangular strips from the inner edge of ground and using inverted L-shaped central feeding stub. The L-shaped stub is oriented at 90 degree with respect to grounded strips. The impedance bandwidth of the antenna proposed here varies from (4.68 - 6.42 GHz) which is 31.3% and the axial ratio bandwidth (<3 dB) is from (5.15-6.45 GHz) which is 22.4% for WLAN (ranging from 5.15 to 5.85 GHz) and WIMAX (5.8GHz,5.5 GHz) applications. The antenna is left and right hand circularly polarized in Z>0 and Z<0 directions respectively. A wide notch is cut from the ground which enhances the ARBW by 51.35% in comparison to simple square shaped ground. All the results have been simulated successfully.
关键词： circular polarization (CP),axial ratio bandwidth (ARBW),slot antenna,coplanar waveguide (CPW),wireless LAN
更新于2025-09-23 15:22:29
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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) - Broadband Circularly Polarized Monopole Antenna with an Open loop
摘要： A broadband circularly polarized (CP) monopole antenna with an annular open-loop is presented. By introducing a gap on the loop, the presented antenna features broadband and produces a bidirectional CP radiation. The simulated results show that the proposed antenna has the advantage of broadband CP characteristics in terms of an impedance bandwidth with S11< -10 dB of 96.1% from 2.7 to 7.7 GHz and a 3-dB axial ratio (AR) bandwidth of 81.3% in the frequency range of 2.7 to 6.4 GHz.
关键词： circular polarization,Loop antenna,broadband,monopole antenna
更新于2025-09-23 15:22:29
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[IEEE 2018 IEEE 15th International Conference on Group IV Photonics (GFP) - Cancun (2018.8.29-2018.8.31)] 2018 IEEE 15th International Conference on Group IV Photonics (GFP) - Photonic Bonding Modes with Circular Polarization at Zero-Group-Velocity Points
摘要： Breaking the parity symmetry of a photonic crystal waveguides can lead to the bonding of guided modes with orthogonal dominant polarizations. Here we present how this coupling allows anomalous zero-group-velocity and prominent circular polarization to emerge, which can be used to enhance uni-directional photon emission. confined aZGV points along with circular polarization points in high field intensity region. Fabricated devices in Silicon-On-Insulator (SOI) wafer confirms modes coupling and an extremely large slow-down factor[11]. This paradigm opens the way for designing outclass chiral quantum photonics circuit.
关键词： photonic crystal waveguides,circular polarization,zero-group-velocity
更新于2025-09-23 15:22:29
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Sources of heading errors in optically pumped magnetometers operated in the Earth's magnetic field
摘要： When optically pumped magnetometers are aimed for use in the Earth’s magnetic field, the orientation of the sensor to the field direction is of special importance to achieve accurate measurement results. Measurement errors and inaccuracies related to the heading of the sensor can be an even more severe problem in the case of special operational configurations, such as the use of strong off-resonant pumping. We systematically study the main contributions to the heading error in systems that promise high magnetic field resolutions at the Earth’s magnetic field strengths, namely the nonlinear Zeeman splitting and the orientation-dependent light shift. The good correspondence of our theoretical analysis to experimental data demonstrates that both of these effects are related to a heading-dependent modification of the interaction between the laser light and the dipole moment of the atoms. Also, our results promise a compensation of both effects using a combination of clockwise and counterclockwise circular polarization.
关键词： optically pumped magnetometers,circular polarization,Earth's magnetic field,light shift,nonlinear Zeeman splitting,heading error
更新于2025-09-23 15:22:29
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[IEEE 2018 International Conference on Electromagnetics in Advanced Applications (ICEAA) - Cartagena des Indias (2018.9.10-2018.9.14)] 2018 International Conference on Electromagnetics in Advanced Applications (ICEAA) - Antenna Pattern Effects in a Low Sidelobe Circularly Polarized Planar Array Due to Element Errors
摘要： Random amplitude and phase errors at the elements of a phased array antenna cause elevated sidelobe levels. Formulas for predicting the sidelobe levels based on the error statistics are well known. These same random errors also cause an error in the axial ratio of a circular polarized array. This paper presents some new expressions for the change in axial ratio as a function of the random errors.
关键词： antenna arrays,axial ratio,planar arrays,circular polarization,array errors,crossed dipoles
更新于2025-09-23 15:22:29
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12- and 21-GHz Dual-band Dual-circularly Polarized Offset Parabolic Reflector Antenna Fed by Microstrip Antenna Arrays for Satellite Broadcasting Reception
摘要： In December 2018, satellite broadcasting for 4K/8K ultra-high-definition television (UHDTV) will begin in Japan. It will be provided in the 12-GHz (11.7 to 12.75 GHz) band with right- and left-hand circular polarizations. BSAT-4a, a satellite used for broadcasting UHDTV, was successfully launched in September 2017. This satellite has not only 12-GHz-band right- and left-hand circular polarization transponders but also a 21-GHz-band experimental transponder. The 21-GHz (21.4 to 22.0 GHz) band has been allocated as the downlink for broadcasting satellite service in ITU-R Regions 1 (Europe, Africa) and 3 (Asia Pacific). To receive services provided over these two frequency bands and with dual-polarization, we implement and evaluated a dual-band and dual-circularly polarized parabolic reflector antenna fed by 12- and 21-GHz-band microstrip antenna arrays with a multilayer structure. The antenna is used to receive 12- and 21-GHz-band signals from in-orbit satellites. The measured and experimental results prove that the proposed antenna performs as a dual-polarized antenna in those two frequency bands and has sufficient performance to receive satellite broadcasts.
关键词： microstrip antenna,dual band antenna,circular polarization,reflector antenna,dual polarized antenna
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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Design of Circular Waveguide Annular Slot Coupled Two-layer DRA for Linear and Circular Polarizations
摘要： The design of a circular-waveguide coupled two-layer DRA configuration is presented. It is observed that besides a reduction in the layers compared to a rectangular waveguide coupled number of multilayer-DRA structure to achieve coupling and enhanced bandwidth, the current configuration significantly enhances the functionality of the design in the realization of dual-band and right-hand / left-hand circularly-polarized (RHCP / LHCP) configurations without the use of additional coupling or matching elements, which to the best of our knowledge has not been reported earlier. Radiation characteristics with low cross-pol are achieved for the linearly polarized dual-band antenna structure. For the circularly-polarized (CP) configurations, a good axial-ratio performance and a high isolation between the RHCP and LHCP fields are achieved. The computed results are obtained through a full-wave Green’s function analysis of the structure, with the thickness of the ground-plane modeled as an annular cavity.
关键词： Dielectric resonator antenna,dual-band,Green’s function,circular polarization,circular waveguide
更新于2025-09-23 15:21:01
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45?° Linearly Polarized and Circularly Polarized High-Scanning-Rate Leaky-Wave Antennas Based on Slotted Substrate Integrated Waveguide
摘要： A class of 45? linearly polarized and circular polarized high scanning rate leaky wave antennas are proposed in this paper, which is based on slow-wave substrate integrated waveguide structure. High scanning rate leaky wave antennas have recently become attractive for imaging applications and automotive radar. These applications also require a continuous scanning range without an open stopband, as seen at broadside for ordinary leaky wave antennas. Furthermore, both 45? linearly polarization and circularly polarization are required in practical applications. In this paper, we propose an all-in-one leaky wave antenna design, which features high scanning rate, continuous scanning capability across the broadside, 45? linear polarization or circularly polarization, single-layer configuration, and single-side radiation. Two design examples are provided to illustrate the proposed principle. Both simulation and experimental validation are given.
关键词： open stopband,Leaky wave antenna,substrate integrated waveguide,circular polarization,scanning rate,linear polarization
更新于2025-09-23 15:21:01
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An enhanced circular polarization near-field focused antenna array by director patches
摘要： This paper presents an enhanced circular polarization (CP) near-field focused (NFF) antenna array. There exist three advantages for the CP NFF antenna. First, this study provides an effective way to realize the CP and NFF simultaneously and do not need to design a specific patch shape for CP, which provides more freedom to change the patch shape for improving other performances. The effective way is arranging the element excitation according to maximum power transmission efficiency theory under the condition of a CP testing antenna. Second, the array element consists of a driven and director patches, and the director patches tilt the element beam from broadside direction to focal point, and then obviously enhance the electric field focusing gain. Third, the proposed array antenna achieves much less size of focal point by using much less element number than published papers. The curves for the impedance and axial ratio (AR) as function of frequency, focus width and depth are analyzed. The simulated and measured results basically agree.
关键词： antenna array,circular polarization (CP),near-field focused (NFF) antenna,director patch
更新于2025-09-23 15:21:01