1,721,213 research outputs found
LP-RLSA design for low-cost transportable basylis radar [Antenna applications corner]
No full textThe increase in small, distributed facilities expected in the near future has raised the necessity of having low-cost, transportable radar systems. In turn, this requires the design of high-gain, low-cost, planar, robust, and easy-to-assemble antennas. In this scenario, the possibility of using a laser-cutting technology in manufacturing a linearly polarized radialline slot array (RLSA) has been investigated. An ad hoc optimization algorithm, which takes into account the physical mechanism beyond the radial-line slot array antenna, has been developed to obtain low antenna sidelobe levels, as required by the specific BASYLIS radar application. The optimization technique allows using near-resonance radiating slots and canceling slots that are all closely spaced on the upper plate of the radial-line slot array. The measurements carried out on the antenna prototype showed very good performance, despite the use of low-cost materials and manufacturing technology
Automatic Design of CP-RLSA Antennas
No full textIn this paper a procedure is presented, allowing the automatic design of circular polarized radial line slot antennas, with either pencil or shaped beam patterns. The antenna slot layout is refined by an optimization scheme based on the physical picture behind the working mechanism of the array. The validity of the approach has been proved by designing very efficient pencil beam
antennas, either with maximum directivity or with controlled side lobe levels, and a shaped isoflux beam antenna
Double-Spiral Linearly Polarized RLSA
No full textHigh gain linearly polarized radial line slot arrays (LP-RLSA) suffer from remarkable degradation of the return loss. To overcome this drawback, this communication presents a novel LP-RLSA design obtained by the superposition of two spirally arranged circularly polarized RLSAs. Indeed, it benefits from the intrinsically low reflection coefficient proper of these circularly polarized spirally arrayed RLSAs. Furthermore, the new layout shows high polarization purity, still maintaining the intrinsic manufacturing simplicity of a RLSA antenna. An antenna prototype has been manufactured and measured to validate the design idea
RADAR OBSTACLE DETECTOR FOR A RAILWAY CROSSING
No full textA radar obstacle detector for a railway crossing having a radar beam with a reduced vertical angle is disclosed. The radar obstacle detector may comprise a waveguide; a transmitting element for emitting microwaves, the transmitting element being positioned in the waveguide; a sectoral horn coupled to the waveguide, wherein the sectoral horn is configured to radiate a radar beam having an angle of 6 to 0 degrees in the plane of flared sides; and a dielectric insert inserted into a first aperture of the sectoral horn
On the Features of Curved Passive Electromagnetic Skins
Full text linkIn this communication, the features of curved passive smart electromagnetic skins working at
millimeter waves to be mounted on street lights or stop light poles are presented and compared to those of the classic planar solution
Optimization-based Design of Isoflux Reflectarray
Full text linkIn this communication, some preliminary results on the design of an isoflux reflectarray, suitable for being mounted on board a satellite or even a CubeSat, carried on with a global optimization technique, are presented. The obtained radiation patterns, relative to a small-medium size configuration, are good and confirm the effectiveness of the proposed procedure
Fast analysis of large finite arrays with a combined multiresolution-SM/AIM approach
Full text linkWe present a synthesis of the sparse matrix/adaptive integral method (SM/AIM) and the multiresolution (MR) approach for the analysis of electrically large finite arrays, with planar or 3-D radiating elements; the two methods were separately introduced previously. The use of the MR has the effect of a preconditioner and speeds up the convergence rate of the SM/AIM of almost two orders of magnitude, with a total reduction of the numerical complexity with respect to the standard MoM of almost three orders of magnitude
An Efficient Full-Wave Method of Moments Analysis for RLSA Antennas
No full textHere a computationally efficient method of moments (MoM) formulation is presented for the full-wave analysis and design of radial line slot antennas (RLSAs). The method efficiency is based on an ad-hoc representation of the internal problem (electrically large circular cavity) Green's function, which is split into the sum of a parallel plate waveguide contribution and a rim effect contribution, expanded in terms of radial modes. The convergence rate of the proposed Green's function expansion is investigated both analytically and numerically with the aid of some examples. Furthermore, comparisons with a commercial general purpose MoM software were performed on a complete RLSA to demonstrate the accuracy and the efficiency of our approach
Additive Manufacturing Folded Reflectarray
Full text linkA 3D printed folded reflectarray that uses fully dielectric resonator elements and a spherical polarizer realized with a metalized plastic structure is presented in this paper. To reduce the thickness of the reflecting surface, a 3D printable dielectric material with a high-value of the dielectric constant is used, while the spherical polarizer is exploited to enhance the reflectarray bandwidth compared to a flat configuration. Preliminary results show very good performance of the antenna, with a gain of about 28 dBi and an efficiency greater than 50% in the whole 1-dB bandwidth of 13.4%
Plug-in vehicle with air heating and dehumidification module
No full textA plug-in vehicle comprising an electrical plug (2) connectable to an external electrical power supply, and at least one air heating and dehumidification module (10) comprising an air inlet duct configured for mixing a first air flow taken from the outside of said vehicle and a second air flow taken from a passenger compartment (120) of said vehicle, a treated air outlet duct configured to input in said passenger compartment (120), an exhaust air outlet duct configured to input in an external environment, a reactor comprising absorbent substances and being interposed between said air inlet duct and said treated air outlet duct or said exhaust air outlet duct, a heating section upstream of said reactor or integrated in said reactor, said heating section being selectively activable by a power supply through said electrical plug (2), for heating an air flow to be circulated in said reactor
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