Romain Siragusa

Tunable Near-Field Focused Circular Phase-Array Antenna for 5.8-GHz RFID Applications

An RFID-compatible focused circular phase-array antenna working at 5.8 GHz is proposed, which is theoretically analyzed and experimentally demonstrated. It consists of 24 half-wavelength dipole antennas placed on three circles. Using only two phase-shifters, a tunable focal spot in the range of 0.4-1 m (10λ) is obtained. The antenna system is analyzed using the Huygens-Fresnel theory, which is compared to the experimental results. At a focal distance of 0.9 m, the measured beam width and focal depth are given by 0.75λ and 5λ, respectively, which are in agreement with the calculated results.

A Tapered CRLH Interdigital/Stub Leaky-Wave Antenna With Minimized Sidelobe Levels

A nonuniform (NU) tapered composite right/left-handed (CRLH) leaky-wave antenna (LWA) with minimized sidelobe level (SLL) is proposed. The design of this antenna is performed using an automated cosimulation approach based on a genetic algorithm optimization. Fair agreement is found between the full-wave and the experimental results. The experimental results show an 8-dB SLL reduction compared to a uniform CRLH LWA with the same gain in a 12-unit-cell structure.

Toward RCS Magnitude Level Coding for Chipless RFID

Hybrid coding techniques have been proposed recently to improve the coding capacity of chipless RF identification (RFID) tag. This paper examines the possibility to code information thanks to the magnitude level of the radar cross section (RCS) in addition to the more classical technique of frequency position (FP). Single-layer tags based on C-folded dipoles are designed to have different magnitude levels. A magnitude span of up to 15.2 dB is obtained for coupled resonators. A magnitude resolution of 3.5 dB is evaluated for practical applications based on the measurement of the realized tags in different configurations. The problem of tags applied to an unknown object is considered and a compensation technique is proposed for an object similar to a thin dielectric plate.

Near field focusing circular microstrip antenna array for RFID applications

A circular microstrip array with beam focused for RFID applications was presented. An analogy with the optical lens and optical diffraction was made to describe the behaviour of this system. The circular configuration of the array requires less phase shift and exhibite smaller side lobe level compare to a square array. The measurement result shows a good agreement with simulation and theory. This system is a good way to increase the efficiency of RFID communication without useless power. This solution could also be used to develop RFID devices for the localization problematic. The next step of this work is to design a system with an adjustable focus length.

Low cost low sampling noise UWB Chipless RFID reader

This paper presents a potentially low cost low sampling noise reader for the Ultra Wideband (UWB) Chipless Radio Frequency Identification (RFID) technology. The reader is designed around the time equivalent approach to reduce its realization cost. A significant effort has been spent for the schematic and layout optimization in order to obtain a very low sampling noise system. This latter aspect is very important to realize a suitable reader for UWB RFID Chipless technology. It is demonstrated that with an accurate design, is possible to realize a low cost equivalent time acquisition system with performances comparable with a high cost real time acquisition system. It is possible acquiring, an UWB impulse of only 70 ps width with high precision.

RFID tags localization along an axis using a tunable near-field focused circular-phase array antenna

A novel concept for RFID tag localization using a tunable near-field focused circular-phase array antenna working at 5.8 GHz is presented. It serves as the reader antenna and focuses the power into a small region, in the tag vicinity. By scanning the focal spot along one axis and monitoring the differential scattered power by a tag, its position along the axis is easily computed with good accuracy. This simple localization scheme is well adapted for specific localization scheme, for example for objects placed over a conveyor belt.

A Concept of Pressure Sensor Based on Slotted Waveguide Antenna Array for Passive MMID Sensor Networks

The concept presented in this paper proposes to exploit the structure of a 3-D slotted waveguide antenna array (SWAA) to turn it into a completely passive millimeter-wave identification (MMID) pressure sensor. The pressure sensor is realized by ending the SWAA with a metallic membrane, where the variation of pressure causes a variation in the radar cross section (RCS). The concept is studied across the RCS measurement of the SWAA ended by a sliding short circuit to emulate the membrane deflection. Experimental results show that a sensitivity of 22.46 mm2/mm of short-circuit displacement is reached at 57.8 GHz. An estimated read range of 1.1 m is considered with an MMID reader compliant with the ETSI European power emission regulation.

RCS magnitude coding for chipless RFID based on depolarizing tag

An approach for coding information based on the magnitude level of the radar cross section (RCS) of depolarizing chipless tags is proposed for the first time. It is used in combination with the classical frequency coding to increase the coding capacity. The control of the magnitude is based on the polarization mismatch between the tag and the reader antenna and it is fully compatible with a recent technique allowing reliable detection in real environments. The theoretical approach is validated by measurements.

A Method to Characterize the Frequency-Dependent Structural Coefficient of Antennas: Application to Millimeter Wave Identification

The passive UHF RFID technology, well known for the logistics and security applications, is more and more considered for sensor networks and Internet of Things (IoT). Recent works have demonstrated the possibility to exploit the main advantages of RFID in the millimeter-wave domain, giving rise to the millimeter wave identification (MMID) technology. This new technology uses the large available ISM band from 57 to 66 GHz in Europe. In backscatter communications, such as RFID or MMID, the radar cross section (RCS) is a fundamental parameter. The antenna RCS is defined as a function of its load and its structural coefficient. The structural coefficient that depends on the antenna geometry is often approximated to unity in RFID because tag antennas are usually thin dipoles compared to the wavelength. However, in MMID this approximation is no longer suitable due to the use of high directive antennas. This letter aims to propose a method to determine the structural coefficient of any types of antenna. The proposed approach is illustrated through the study of a horn antenna and a slotted waveguide antenna array in WR15 waveguide (from 50 to 75 GHz). Theoretical, simulation, and measurement results are compared and demonstrate the interest of the method.

Generalized Array Factor Approach to the Assessment of Discrete Tapered Nonuniform Leaky-Wave Antenna

A generalization of the array factor approach of a nonuniform leaky-wave antenna (LWA) is proposed for the modeling of discrete tapered LWAs. The demonstration is based on the Fourier transform of the illumination amplitude of an LWA and is thus quite general. This analysis approach can be helpful for design. When it is used in combination with classical taperization techniques, it provides an easy and powerful conception tool. The validity of the method is demonstrated with the Holey and the Honey LWAs. Taylor and cosine distributions were simulated and sidelobe level reduction up to -40 dB were obtained. A Holey antenna designed to work at 1.7 GHz with a cosine distribution was realized. Its radiation pattern was measured and it shows an acceptable agreement with theory and numerical simulations.