A novel chipless RFID humidity sensor based on a finite artificial impedance surface (AIS) is presented. The unit cell of the AIS composed three concentric loops thus obtaining deep and high-Q nulls in electromagnetic response tag. wireless fabricated using low-cost inkjet printing technology thin sheet commercial coated paper. patterned placed metal-backed cardboard layer. relative information encoded frequency shift resonance peaks. Varying level from 50% to 90%, has proved be up 270 MHz....

An overview of transmission/reflection-based methods for the electromagnetic characterisation materials is presented. The paper initially describes most popular approaches bulk in terms dielectric permittivity and magnetic permeability. Subsequently, limitations aimed at removing ambiguities deriving from application classical Nicolson–Ross–Weir direct inversion are discussed. second part focused on partially conductive thin sheets surface impedance via waveguide setups. All presented...

An accurate and simple analytical model for the computation of reflection amplitude phase Reconfigurable Intelligent Surfaces is presented. The based on a transmission-line circuit representation RIS which takes into account physics behind structure including effect all relevant geometrical electrical parameters. proposed allows to take incidence angle, mutual coupling among elements interaction periodic surface with ground plane. It shown that approach design physically realisable without...

A chipless RFID sensor exploiting the depolarizing effect of a finite period surface is proposed for rotation monitoring. The information encoded in cross-polar response scatterer, which, turns, depends on orientation tag with respect to probing wave. Preliminary assessment illustrated and critical issues are analyzed future developments.

A novel normalization-free reading scheme to recover data encoded in chipless radio frequency identification (RFID) tags is presented. The proposed approach exploits the circular polarization isolate field scattered by tag from that of surrounding objects. desired mismatch achieved exploiting properties high-impedance surfaces can suitably manipulate reflected field. thorough analysis interaction between circularly polarized (CP) interrogation and RFID as well hosting platform provided....

An ultra-wideband linear polarization converter based on a reflecting metasurface is presented. The polarizer composed by periodic arrangement of miniaturized metallic elements printed grounded dielectric substrate. In order to achieve broadband converting properties, the optimized employing genetic algorithm (GA) which imposes minimization amplitude co-polar reflection coefficient over wide frequency band. enhanced angular stability due unit cell obtained imposing maximum periodicity in GA...

A novel, chipless, Radio Frequency Identification (RFID) sensor is proposed for monitoring angular rotation. The rotation state recovered by collecting the cross polar response of a tag, based on periodic surface composed set dipoles. encoding mechanism allows to be very robust, even if it applied metallic objects, or in an environment with strong multipath. does not require large operational bandwidth. Instead, only small reading frequencies are required. number required dependent employed...

This paper proposes a D-band absorber that employs periodic resistive surface made of Tantalum Nitride <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$(Ta_{2}N)$</tex> deposited on gold-backed alumina dielectric substrate. The top consists square loop-based unit cells and demonstrates an absorption rate over 90% across the frequency range from 100 GHz to 166 GHz. performance designed is evaluated through full-wave simulation method has been...

A robust technique for reading moving chipless tags exploiting the inverse synthetic aperture radar data processing is presented. The procedure takes advantage from known tag movement to improve detection capability by integrating several received signals. implicit of proposed scheme that background measurement, collected in absence tag, can be easily performed before passes front reader antenna. allows a significant increase interrogation distance and, more importantly, it greatly improves...

The performance of different chipless RFID tag topologies are analysed in terms Radar Cross Section (RCS) and Bit Error Rate (BER). It is shown that the BER mainly determined by once a standard reading scenario considered fixed size chosen. arrangement resonators plays crucial role determining cross-polar RCS tag. computed theoretically using array theory where each resonator treated as separate scatterer completely characterized specific reflection coefficient. Several arrangements...

A low-profile microstrip patch antenna has been designed for tuning on a discrete set of instant frequencies. The frequency reconfigurability is obtained by resorting to electrically actuated switches operated via software-controlled biasing network. low-cost PIC microcontroller employed control the operative condition among available states. Measurements fabricated prototype show good matching with simulations and prove reliability proposed configuration.

A novel iterative procedure for designing multiband single-layer reflectarrays is presented. The frequency behavior achieved by simultaneously providing the desired phases at each operating frequency. suitable reflectarray element shape formed several concentric loops loaded with double stubs has been selected achieving operation. problem of mutual coupling among different selfsimilar resonating elements laying on same substrate analyzed and mitigated employing an innovative design approach....

Chipless technology is based on the modulation of backscattered signal. The challenge in designing chipless RFID sensors how to perform data encoding without presence a chip and adding sensing capability. aim this work investigate design able face these challenges.

An equivalent circuit model for Frequency Selective Surfaces (FSS) comprising anisotropic elements is presented. The periodic surface initially simulated with an arbitrary azimuthal incidence angle and its impedance matrix derived. subsequently rotated by $\varphi^{rot}$ on the crystal axes $\chi_1$, $\chi_2$ thus nullifying extra diagonal terms. rotation derived according to spectral theorem using terms of extracted. matrix, that is, impedances $Z_{\chi_1}$ $Z_{\chi_2}$, are finally matched...

A simple but efficient approach for the synthesis of transmission-type wideband polarization converters is presented. The proposed configuration comprises multilayer metasurfaces including resonant particles which are progressively rotated layer by layer. progressive rotation allows a conversion over large frequency band. polarizing structure efficiently designed and optimized through transmission line model handling cascade anisotropic impedance layers dielectrics. An 8-layers design based...

A chipless RFID tag that exhibits a variable cross-polar response depending on its orientation with respect to the probing wave is investigated as potential candidate for realizing an angular rotation sensor. The sensor can be employed in harsh environments due absence of any silicon chip.

A rigorous and efficient approach for the design of radomes that are closely spaced to radiating aperture a phased array is proposed. The method relies on generalized scattering matrix (GSM) description both source radome based Floquet modal expansion. GSM unit cell calculated only once. radome, which also frequently addressed as wide-angle impedance matching, optimized simply by iterating with fast solver periodic moments. effect antenna taken into account through connection matrices....

A novel depolarizing chipless tag configuration with high angular insensitivity is presented. The basic comprises two dipole resonators arranged a relative rotation of 45°. proposed improves the depolarization properties performance single over ground plane which provides peak perfect polarization conversion only if electric field impinges at 45° respect to resonator. second compensates cross-polar reduction observed when not correctly polarized. Indeed, tilted by 90° first dipole, it forms...

ART-PO algorithm for the estimation of Radar Cross Section electrically large targets coated with radar absorbing materials is presented. The proposed method relies on calculation reflection coefficient multilayer structure (metallic surface covered material) a Periodic Method Moments. also evaluated by using simplified transmission line model comparison. applied to metallic corner reflector partially resistive Frequency Selective Surface.

A novel ink-jet printed chipless RFID humidity sensor is presented. The sensor, based on a finite Artificial Impedance Surface (AIS), thin sheet of Mitsubishi paper, which placed metal-backed cardboard layer. frequency response the AIS provides three deep nulls thanks to nested loops that constitute unit cell periodic surface. interaction between and results in variation electric permittivity paper and, consequently, shift resonance peaks. exhibits peaks 270MHz with level from 50% 90%....

The challenge in designing chipless RFID sensors is to obtain a reliable and replicable estimation of environmental parameters. aim this work investigate two promising sensor configurations able face these challenges.

A hybrid method based on Ray Tracing and Physical Optics for the estimation of radar cross section large metallic targets covered with absorbing materials is presented. The reflection coefficient multilayer structure composed by layer analytically evaluated through a transmission line model. accuracy Radar Cross Section validated full-wave simulations Method Moments. corner reflector coated Absorbing Material (RAM) used as test-case proposed method. obtained results exhibit good agreement if...

An ultra-wideband linear polarization converting metasurface is presented. The polarizer based on a periodic arrangement of metallic elements printed grounded dielectric substrate. element geometry the optimized with genetic algorithm by discretizing unit cell in 16×16 pixel matrix. This converter able to work from 7.03 GHz 29.01 (121% bandwidth) cross polar reflection coefficient greater than -2 dB. A refinement also applied order further extend operative bandwidth and at same time remove...