A breadboard of a three-layer printed reflectarray for dual polarization with different coverage in each has been designed, manufactured, and tested. The consists three layers rectangular patch arrays separated by honeycomb backed ground plane. beam shaping is achieved adjusting the phase reflection coefficient at reflective element independently linear polarization. shift controlled varying either <tex xmlns:mml="http://www.w3.org/1998/Math/MathML"...

A 1.2-meter reflectarray antenna has been designed to accomplish the requirements of a Direct Broadcast Satellite (DBS) mission, which provides South America transmit-receive coverage in Ku band. The by applying first all pattern synthesis technique obtain required phase distribution on at several frequencies transmit and receive bands. Then, patch dimensions have optimized configuration made three stacked layers varying-sized patches order provide frequencies. An demonstrator manufactured...

A machine learning technique is applied to the design and optimization of reflectarray antennas considerably accelerate computing time without compromising accuracy. In particular, support vector machines (SVMs), automatic structures that are able deal with regression problems, employed obtain surrogate models element substitute full-wave analysis tool for characterization unit cell in algorithms. The analysis, design, a very large antenna Direct Broadcast Satellite applications accelerated...

In recent years, artificial intelligence (AI) techniques have been developed rapidly. With the help of big data, massive parallel computing, and optimization algorithms, machine learning (ML) (more recently) deep (DL) strategies equipped with enhanced generalization capabilities. Besides becoming an essential framework in image speech signal processing, AI has also widely applied to solve several electromagnetic (EM) problems unprecedented computational efficiency, including inverse...

Mechanical beam steering using a single transmitarray (TA) can be cost-effective solution for high-gain antenna with wide-angle scanning. Elevation scanning achieved by linear displacement of the feed in focal plane parallel to aperture diameter D. When designing compact terminals short length F and high gain, aberrations caused this mechanical movement become main limiting factor maximum range. This work presents novel design method devising TA phase correction an even distribution these...

A two-layer reflectarray is proposed as a central station antenna for local multipoint distribution system (LMDS) in the 24.5-26.5 GHz band. The produces three independent beams an alternate linear polarization that are shaped both azimuth (sectored) and elevation (squared cosecant). design process divided into several stages. First, positions of feeds established well geometry to produce required directions. Second, phase on surface, which beam shaping, synthesized. Third, sizes printed...

The design, construction and measured performance is described of an offset parabolic reflector antenna which employs a reflectarray subreflector to tilt the focused beam from boresight direction at 94 GHz. An analysis technique based on method moments (MoM) used design dual-reflector antenna. Numerical simulations were employed demonstrate that high gain pattern can be tilted predetermined angle by introducing progressive phase shift across aperture reflectarray. Experimental validation...

A new approach to designing frequency selective surface (FSS)-based linear circular polarization (LP-CP) converters is presented. It based on the use of FSSs which exhibit dual diagonal symmetry, and a novel four-port equivalent circuit able describe electrical behavior cells for two incident polarizations at same time. The allows standardized branch line coupler theory design LP-CP comprising cascade an arbitrary number layers, whose synthesis includes phase makes it possible achieve...

This paper presents the design, manufacture and test of a low-cost reflectarray antenna that provides sectored-cosecant squared beam. The bandwidth limitation single-layer reflectarrays is overcome by using three parallel dipoles in each cell. First, relative length chosen to improve element bandwidth. Then, dipole dimensions are adjusted generate sectored beam azimuth cosecant elevation. A prototype has been manufactured tested. measured radiation pattern compared with results approximate...

A dual-offset reflectarray demonstrator has been designed, manufactured and tested for the first time. In antenna configuration presented in this paper, feed, sub-reflectarray main-reflectarray are near field one to each other, so that conventional approximations of far not suitable analysis antenna. The is designed by considering near-field radiated horn contributions from all elements compute required phase-shift on element main reflectarray. Both reflectarrays have using broad-band based...

A method for the optimization of crosspolar component dual-polarized reflectarrays using full-wave analysis at element level is described and demonstrated. The reflectarray based on local periodicity (LP) integrated within process in order to accurately characterize far field. proposed generalized Intersection Approach framework Levenberg-Marquardt Algorithm as backward projector, employed Method Moments assuming Local Periodicity (MoM-LP). Several strategies accelerate computations are...

Abstract One of the most ambitious projects in communications recent years is development so-called satellite mega-constellations. Comprised hundreds or thousands small and low-cost satellites, they aim to provide internet services places without existing broadband access. For antenna subsystem, reflectarrays have been proposed as a cheap solution due their low profile manufacturing costs, while still providing good performance. This paper presents full design reflectarray for...

This paper describes the characterization of reflectarray unit cells using support vector machines (SVMs) to obtain fast and accurately full matrix reflection coefficients, which is used for an analysis dual-polarized reflectarrays, demonstrating performance model. First, a surrogate model cell obtained SVMs. To this end, set random samples coefficient with full-wave method moments based on local periodicity (MoM-LP) train efficiently model, novel strategy accelerate training process...

In recent years, machine learning techniques (MLTs) have been applied to accelerate the analysis and design of electromagnetic devices. Algorithms such as artificial neural networks or support vector machines for regression (SVRs) proposed large reflectarrays space applications at a single frequency. However, multifrequency optimization antennas has not tackled with MLTs. this letter, first time, we propose technique based on use SVR obtain reflection coefficients very shaped-beam...

In this work, a reflectarray is proposed to be used as probe of reduced and portable compact-antenna-test range for 5G new radio devices. The works at 28 GHz produces quiet zone in the near-field region antenna. Considering that specifications are established terms amplitude phase ripple, synthesis technique presented optimize near field Fresnel with constraints. based on generalized intersection approach using Levenberg-Marquardt algorithm its backward projector obtaining novel synthesis....

This work presents an array of slot-type elements fed by a corporate network, achieving several radiation patterns in the mm-Wave band. The antenna is based on metal-only structure, with feeding network implemented using Groove Gap Waveguide technology, resulting low-loss, highly scalable solution. radiating are slots 1 × 8 configuration, which excited through three waveguide ports. proposed allows for sum pattern that can also steer beam depending port. Additionally, difference be obtained....

A mechanical beam-scanning reflectarray (RA) antenna is presented for Ka band. The 1D steering of the beam achieved through linear in-plane panel translations, which can be implemented at low cost using a rail-mounted moving RA panel. Compared to related works, highly uniform level with remarkably compact profile. new technique also proposed mitigate high side lobes caused by optics, achieving an estimated 2.3 dB reduction in maximum SLL. manufactured prototype has size 256.4 187.2 mm 2898...

A shaped-beam reflectarray based on patches, aperture-coupled to delay lines is demonstrated for local multipoint distribution system (LMDS) central station antennas, in the 10.10-10.70 GHz band. The antenna must cover a 60 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">deg</sup> -sector azimuth with squared cosecant pattern elevation. design process consists of two steps. First, phase-only synthesis technique applied obtain required...

A modular technique for the analysis of a dual-reflectarray antenna (DRA) configuration is presented. The proposed method has been used to design DRA that emulates previous dual-reflector antennas in Ku- and W-bands including reflectarray as sub-reflector. results compare very well with those parabolic reflector sub-reflector; radiation patterns, gain efficiency are practically same when main substituted by flat reflectarray, being reduced few tenths dB result ohmic losses reflectarray....

The accurate measurement of the permittivity, loss tangent and dielectric anisotropy DC bias dependence for two different liquid crystal (LC) materials in frequency range 140–165 GHz is described. electrical characteristics are obtained by curve fitting computed transmission coefficients to experimental spectral response a new class electronically reconfigurable selective surface. periodic structure designed yield bandpass filter with without an applied control voltage order measure...

This communication presents a dual-band design procedure applied to very large contoured-beam reflectarray with improved copolar and cross-polarization performances for direct broadcast satellite (DBS) in dual-linear polarization. The is elliptical, the axes of 1.10 1.08 m, provides coverage South America transmit (11.70-12.20 GHz) receive (13.75-14.25 bands. novel approach based on use multiresonant unit cell several degrees freedom (DoFs). It divided into stages facilitate convergence...

An analysis technique is proposed for the of reflectarrays placed in Fresnel zone primary feed. The based on classic considering local periodicity, improved by near field radiated feed horn instead ideal models. incident each reflectarray cell obtained applying transformation to measured far (FF) antenna. stronger variation considered increasing number samples per and reflected waves. This enhanced has been applied a multi-fed multiple-shaped beam horns. antenna was as central station...

A 1.1-m reflectarray antenna has been designed, manufactured, and tested to fulfill the requirements of a satellite in Ku-band that provides South-American coverage Tx Rx. The cells consist four dipoles for each polarization two dielectric layers, selected because their simplicity high performance. dipole dimensions are optimized all accomplish prescribed radiation patterns, by iteratively calling an analysis routine based on method moments spectral domain local periodicity. measured...

This contribution describes the design of a reflectarray to produce two adjacent beams per feed in orthogonal circular polarization (CP) simultaneously at transmit (Tx) and receive (Rx) frequencies Ka band. The discrimination CP is achieved by variable rotation technique (VRT), whose dual band operation validated for first time manufacture measurement 25 cm × demonstrator. Moreover, an optimization procedure has been implemented improve narrowband performance VRT (which leads high...