- 标题
- 摘要
- 关键词
- 实验方案
- 产品
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All-Directions Through-the-Wall Imaging Using a Small Number of Moving Omnidirectional Bi-Static FMCW Transceivers
摘要： Through-the-wall radar imaging is a powerful tool for mapping buildings’ interiors and hidden objects behind the walls. Through-the-wall imaging systems require large linear arrays of directive antennas to form a large aperture for obtaining images with a high cross-range resolution. However, the low mobility and limited field of view of the conventional systems limit their imaging capability. The concept of all-directions through-the-wall imaging has recently been proposed to enhance the mobility, cross-range resolution, and field of view of the through-the-wall imaging systems. In this technique, the large linear array of directive antennas is replaced by a dense 2-D synthetic array formed by small moving transceivers utilizing omnidirectional antennas. The 2-D synthetic array provides 360° high cross-range resolution images. This paper focuses on the implementation of a system realizing all-directions through-the-wall imaging and measurement results. A bi-static frequency-modulated continuous wave (FMCW) radar system utilizing a simple wireless synchronization scheme and wideband omnidirectional antennas is fabricated and an image formation technique compatible with bi-static FMCW imaging system is presented. Measurement results show that the imaging system can provide 360° high-resolution image of objects and walls in a short time.
关键词： through-the-wall imaging,Bi-static,frequency-modulated continuous wave (FMCW),circular polarization,synthetic aperture,imaging
更新于2025-09-10 09:29:36
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[IEEE 2018 Second International Conference on Inventive Communication and Computational Technologies (ICICCT) - Coimbatore (2018.4.20-2018.4.21)] 2018 Second International Conference on Inventive Communication and Computational Technologies (ICICCT) - Design of Circularly Polarized Microstrip Patch Antenna with Inserting of Shorting Pins
摘要： This report proposes that for high bandwidth circular polarization microstrip patch antenna along with single-feed is used. On the orthogonal, diagonal of the patch radiator set of pins are placed symmetrically, shorting pins bring Shunt inductive effect. To enhance the electrical size of the patch resonator and to optimize its bandwidth and other parameters in this MPA (microstrip patch antenna) the resonating frequency of the is the progressive tune-up. The maximum disputed mode bandwidth of circular polarization investigates the optimal inserting position. A single pair of internal pins is moderately moved to neatly divide the two disputed modes to get CP radiation. LHCP (left hand circular polarization) or RHCP (right hand circular polarization) perhaps got by varying the feed position along the x and y-axis. After executing extensive analysis, simulation outcomes exhibit a good correspondence and hence prove that the bandwidth is improved from 23MHz to 46MHz, displaying 23MHz (100%) enhancement.
关键词： set of shorting pins,circular polarization,high bandwidth MPA,single probe feed
更新于2025-09-10 09:29:36
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A POLARIZATION RECONFIGURABLE MICROSTRIP ANTENNA EMPLOYING DUAL-PERTURBATION TECHNIQUE
摘要： This study presents a polarization recon?gurable antenna with frequency diversity function. The antenna incorporates a novel positive and negative perturbation technique to achieve di?erent polarization sense. A square shape slot is loaded on the ground plane to excite circular polarization by creating a negative perturbation. An L-shape segment is integrated to the patch using a switching diode. This segment creates a positive perturbation to eliminate the negative perturbation created by the defected ground slot, and the antenna excites linear polarization. Frequency diversity is achieved by exciting di?erent polarization senses at di?erent frequencies. A 3-dB axial ratio bandwidth of 1.41% is obtained for circular polarization radiation while the 10-dB impedance bandwidth during linear polarization is 1.8%. The antenna shows good radiation performances with high gain at both polarization states, and the performances are con?rmed experimentally.
关键词： polarization recon?gurable antenna,linear polarization,frequency diversity,circular polarization,positive and negative perturbation technique
更新于2025-09-09 09:28:46
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RCS Reduction and Gain Enhancement for the Circularly Polarized Array by Polarization Conversion Metasurface Coating
摘要： High-gain, the ultra-wide band circularly polarized (CP) array with low radar cross section (RCS) is proposed based on (UWB) polarization conversion metasurface (PCM) coating. A chessboard-like coating is formed by a mess of arrow-shaped PCM elements which have UWB and high polarization conversion ratio. The coating is distributed beneath the dipoles and behaving as a reflector. With the PCM beneath each dipole, the CP radiation is achieved and enhanced in a low profile by the radiating wave and the reflected wave, which have equal amplitude and 90° phase difference. With the chessboard-like coating, the incident wave is converted into the equal amplitude and out-of-phase reflected waves, which will cancel each other to reduce the backward scattering. The performances of the array are validated by both simulations and measurements. The results show that the left-hand CP radiation is achieved in 11.25 GHz to 12.31 GHz with the RCS being reduced for more than 4.8 dB in 10.5 GHz to 35.1 GHz.
关键词： high gain,circular polarization,low profile,radar cross section (RCS),polarization conversion metasurface (PCM)
更新于2025-09-09 09:28:46
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[IEEE 2018 48th European Microwave Conference (EuMC) - Madrid, Spain (2018.9.23-2018.9.27)] 2018 48th European Microwave Conference (EuMC) - Design of a Wideband Multilayer Meander-Line Polarizer (6 – 18 GHz) using a Semi-Analytical Method
摘要： A semi-analytical method to design multilayer meander-line polarizers is described in this paper. The proposed procedure consists of a combination of the transmission line equivalent circuit and a Simulated Annealing Algorithm to estimate the best values of the dimensions of the polarizer. A wideband four layers’ meander-line polarizer [6 – 18 GHz] is studied. Patch antenna resonating at different frequencies is associated to the polarizer to validate it. The results verify that the proposed multilayer meander-line polarizer convert the Linear wave to Circular one.
关键词： Simulated Annealing Algorithm,Transmission-Line Equivalent Circuit,Meander-line Polarizer,Linear polarization,Wideband Polarizer,Multilayer Structure,Circular polarization
更新于2025-09-09 09:28:46
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Triple-Band Dual-Sense Circularly Polarized Hybrid Dielectric Resonator Antenna
摘要： In this paper, a triple-band dual-sense circularly polarized (CP) hybrid dielectric resonator antenna is proposed. A modified hexagonal dielectric resonator (DR) is top-loaded with a square microstrip ring (SMR). A vertical-tapered-strip connected to a 50-? microstrip line is used to excite the proposed antenna. It is found that the lower and central CP bands correspond to left-handed circular polarization and are produced by the TM11 and TE111 modes of the SMR and modified hexagonal DR, respectively. The upper CP band is formed by the combination of the quasi-TM21 mode of the SMR and quasi-TE111 mode of the DR that exhibits right-handed circular polarization. The measurement results of the fabricated prototype show triple-band response for |S11| < ?10 dB with impedance bandwidths (IBWs) of 17.4% (1.75–2.03 GHz), 28.13% (2.23–2.96 GHz), and 2.97% (3.65–3.76 GHz) in the lower, central, and upper bands, respectively. The measured 3 dB axial ratio bandwidths lying within ?10 dB IBWs are 3.69% (1.86–1.93 GHz), 5.46% (2.67–2.82 GHz), and 2.15% (3.68–3.76 GHz) along with the peak gains of 5 dBic, 5.28 dBic, and 2.36 dBic in the lower, central, and upper bands, respectively.
关键词： hybrid antenna,dielectric resonator antenna (DRA),square microstrip ring,multi-band,triple-band circular polarization
更新于2025-09-09 09:28:46
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[IEEE 2018 XXIIIrd International Seminar/Workshop on Direct and Inverse Problems of Electromagnetic and Acoustic Wave Theory (DIPED) - Tbilisi, Georgia (2018.9.24-2018.9.27)] 2018 XXIIIrd International Seminar/Workshop on Direct and Inverse Problems of Electromagnetic and Acoustic Wave Theory (DIPED) - Directed Circular Polarized Antenna
摘要： The goal of proposed research is to construct the circular polarized narrow-band directed antenna using low-loss dielectric and high relative permittivity material for the substrate. Presented first part contains the simulation of such antenna using the software which based on Finite Element Method for the purpose to fined optimal parameters of such antenna before its construction. Using numerical experiment we suppose to determine best parameters of antenna, to achieve desired radiation parameters: well matched to the open space; circular polarization of radiated field; narrow-beam; wide-ban. It was designed 2.49 GHz and 2.4 GHz circular polarization radiation patch antennas, which was archived by cutting edges from square patch antenna. For simulation it was used 6.8 relative permittivity material for the substrate.
关键词： Patch Antenna,Narrow-band,Circular Polarization
更新于2025-09-09 09:28:46
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[IEEE 2018 IEEE International Conference on Service Operations and Logistics, and Informatics (SOLI) - Singapore (2018.7.31-2018.8.2)] 2018 IEEE International Conference on Service Operations and Logistics, and Informatics (SOLI) - High-Isolated Coplanar-Fed Circularly Polarized 2×2 Curl Antenna for MIMO Applications
摘要： This paper proposes a coplanar-fed circularly polarized curl antenna for MIMO applications, whose feeding element consists of a metal strip and an inner conductor of coaxial line to match the 50Ω system and to ease the fabrication process. The radiation element including a horizontal strip and a curl strip is etched on the Rogers4003C substrate to enhance the robustness of the antenna system. Besides, a design guideline of a high-isolated 2×2 MIMO antenna is provided such that the antenna isolation of > 25 dB can be obtained theoretically. Both the simulation and measurement results are quite in agreement with each other, indicating that the isolation of > 22 dB is achieved within the axial ratio bandwidth of ~ 4%.
关键词： mutual coupling suppression,electromagnetically coupled feeding,circular polarization,angular orientation,curl antenna,MIMO
更新于2025-09-09 09:28:46
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CIRCULAR POLARIZATION FRACTAL SLOT BY JERUSALEM CROSS SLOT FOR WIRELESS APPLICATIONS
摘要： In this letter, a new model of antenna with Jerusalem crosses (JC) as fractal slots for circular polarization applications is designed. The proposed slot antenna has a fractal cross formation with four Jerusalem crosses (JC) to achieve wide bandwidth and a compact size as well as circular polarization. A T-shaped feed line is implemented in the proposed antenna for improving the bandwidth while the interaction of the feed line with cross-shaped slots makes circular polarization. The proposed antenna shows bi-directional pattern and bandwidth at 2.42–3.0 GHz with VSWR < 2, which can be used in Wi-Fi and Bluetooth applications with a gain of 3.5 dBi. The proposed fractal antenna size is 40 × 40 mm, and it is designed and fabricated on an FR-4 low-cost substrate with thickness of 1.6 mm. It is simulated by HFSS full wave software. In addition, the experimental results are presented and compared with the simulation for VSWR, radiation pattern and axial ratio.
关键词： wireless applications,Wi-Fi,Circular polarization,Jerusalem cross slot,fractal slot,Bluetooth
更新于2025-09-09 09:28:46
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Compact Circularly Polarized Wearable Button Antenna with Broadside Pattern for U-NII Worldwide Band Applications
摘要： A novel circularly polarized button antenna is proposed. The antenna is constructed on a disc shaped FR-4 substrate. This disc is located on top of a textile layer and supported by a feeding probe. The antenna works in the 5.47-5.725 GHz U-NII world wide band, with over 14% relative impedance bandwidth and over 7% relative axial ratio bandwidth. A prototype has been fabricated and measured. A good agreement is found between measured and simulated results.
关键词： Wearable,Button antenna,U-NII band,Axial ratio,Circular polarization
更新于2025-09-09 09:28:46