- 标题
- 摘要
- 关键词
- 实验方案
- 产品
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Analysis and design of coaxial nozzle with rectangular outlet for high power diode laser in laser metal deposition
摘要： High power diode laser (HPDL) characterized by a wider rectangle beam spot (RBS) with top-hat intensity distribution is particularly applied in laser metal deposition to manufacture large-scale components. In order to design a coaxial nozzle with rectangular outlet to match the RBS of the HPDL, a novel wide-beam coaxial feeding nozzle (WBCFN) outlet is proposed. Based on the gas-powder flow model established in ANSYS FLUENT, the influence of structural parameters of the new coaxial nozzle on the gas flow and powder distribution is investigated. Two quantitative indexes are defined to seek out the optimal designing scheme that minimize the divergences of the powder flow and uniform the powder distribution in transverse and longitudinal directions. And then, the effect and sensitivity of structural parameters on concentration distribution and focal length of powder flow are analyzed. The results indicate that the two indexes increase with the increase of exit width, while the variance of concentration firstly increases and then decreases with the increase of the chamber length and inclination angle. The focal length decreases with the increase of inclination angle. Finally, the optimal solution of designing scheme is obtained through comprehensive analysis, and experiments are carried out to validate the model, which indicates that the designed WBCFN can acquire good morphology and quality of deposition layer for HPDL.
关键词： Wide-beam coaxial feeding nozzle,Laser metal deposition,Discrete phase model,High power diode laser
更新于2025-09-23 15:21:01
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[IEEE 2019 IEEE Asia-Pacific Microwave Conference (APMC) - Singapore, Singapore (2019.12.10-2019.12.13)] 2019 IEEE Asia-Pacific Microwave Conference (APMC) - A Circularly Polarized Antenna Element Based on Open-ended Waveguide
摘要： Based on the open-ended rectangular waveguide structure, we proposed a circularly polarized antenna element with wide axial-ratio (AR) beam-width in this communication. Two rectangular notches are distributed on the wide sides of a rectangular waveguide in a 180° rotational symmetry to excite circular polarization. The simulated RHCP gain of the antenna is about 3.2 dBic at 11.5 GHz and the 3-dB AR beam-width is more than 120°. In addition, Owing to its simple configuration, the compact size (12(cid:2)(cid:2)6 mm2), this antenna element lays a good foundation for circularly polarized array antennas in wireless communication applications.
关键词： Circular polarization,End-fire antennas,Waveguide antennas,Wide beam-width
更新于2025-09-23 15:19:57
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Wide-angle scanning circular polarization phased array based on polarization rotation technology
摘要： A wide-beam circular polarization (CP) antenna and a wide-angle scanning phased array based on novel polarization rotation reflective surface (PRRS) are proposed. The CP wide-beam pattern is obtained by the combination of the radiation wave from the patch antenna and the orthogonal reflected wave from the PRRS with a 90(cid:1) phase difference. The proposed CP wide-beam antenna obtains the patterns with the 3-dB beamwidth more than 136(cid:1) and the axial ratio (AR) beamwidth more than 132(cid:1) in the xoz-plane. Furthermore, an eight-element phased array based on the wide-beam CP antenna element is also developed. The measured results show that the main beam of the array can scan from ?65(cid:1) to 65(cid:1) with a gain fluctuation less than 3 dB and the ARs at every scanning angle less than 3 dB.
关键词： polarization rotation,phased array,wide-beam,circular polarization,wide-angle scanning
更新于2025-09-19 17:15:36
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SIW Based Leaky-Wave Antenna Supporting Wide Range of Beam Scanning through Broadside
摘要： In this letter, a substrate integrated waveguide (SIW) based leaky wave antenna with wide beam scanning is presented to mitigate open stopband (OSB). The unit cell of this proposed antenna consists of a longitudinal slot and a post placed oppositely offset from the center line. By introducing inductive post along with longitudinal slot in each unit cell, the open stopband is suppressed resulting continuous beam scanning. An equivalent circuit of the proposed unit cell is developed to explain impedance matching technique used here to suppress OSB. Dispersion diagram is also used to analyze this seamless scanning. This antenna can scan from -49° to +69° through broadside because of wide impedance matching. Finally, the antenna is prototyped and experimentally verified. Measured results are in accord with simulated results. This antenna provides maximum gain of 14.2dBi and low level of cross-polarization.
关键词： SIW,wide beam-scanning,impedance matching,leaky wave antenna,open stopband
更新于2025-09-19 17:15:36
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COMPACT WIDE-BEAM CIRCULARLY POLARIZED ANTENNA WITH STEPPED ARC-SHAPED ARMS FOR CNSS APPLICATION
摘要： A single-feed circularly polarized wide-beam antenna is proposed for Compass Navigation Satellite System (CNSS) application. The antenna consists of four stepped arc-shaped arms, which are applied to generate circularly polarized radiation. To broaden the beamwidth, each arm is split up into two horizontal arc-shaped parts and one vertical part. The proposed antenna is simulated, fabricated and tested. The measured results show that the 10-dB return loss band of the proposed antenna is from 2.37 GHz to 2.65 GHz and the 3-dB axial ratio band from 2.42 GHz to 2.55 GHz, covering the receiving band (2.49175 GHz ± 4.08 MHz) of CNSS. Its 3-dB AR beamwidth is 181? at 2.491 GHz. For the horizontal radiation pattern of the proposed antenna at 5? elevation angle, the RHCP gain is greater than ?1.1 dBic, and the out-of-roundness is 1 dB. Additionally, the proposed antenna has a size of 0.37λ0 × 0.37λ0 × 0.11λ0 with respect to 2.491 GHz.
关键词： wide-beam,stepped arc-shaped arms,Circularly polarized,CNSS
更新于2025-09-04 15:30:14