Combined RFID Tag Antenna for Recipients Containing Liquids

International audienceIn UHF RFID (radio frequency identification), passive tag antennascan be fixed on boxes or recipients where the nature and contentsmight vary. These variations strongly affect the antenna performance.A combined antenna is proposed to ensure an effective read-range for aplastic recipient containing water or not. Two separate antennas arefirst designed for the filled and unfilled cases, respectively, thencombined for a correct working in both configurations

Étude et réalisation de antennes diélectriques pour les applications satellitaires et corps (BAN)

Dans cette thèse, on vise deux types d'applications de l antenne à résonateur diélectrique (DRA): 1) La réalisation d un élément rayonnant pour un réseau phasé embarqué sur un véhicule terrestre ou un avion. Cet élément de base requiert une couverture en élévation supérieure à celle des éléments imprimés pour permettre une poursuite typique comprise entre +-70. La couverture dans un cône large est assurée avec une bonne pureté de polarisation circulaire en alimentant l antenne à travers deux ouvertures à fente en H orthogonales parfaitement découplées en bande X. 2) La deuxième structure est destinée à la diversité d antennes dans le contexte des réseaux corporels embarqués ou Body Area Network (BAN). L antenne à diversité combine une antenne fente en boucle avec un DRA ce qui permet dans un espace compact de réaliser des diagrammes de type broadside et endfire respectivement. Les alimentations considérées sont de 2 types; Soit purement planaire (microruban et coplanaire) soit mixte en combinant une alimentation coaxiale et une alimentation coplanaire. Caractéristiques principales des antennes à résonateur diélectrique (DRA): Pour répondre aux attentes des utilisateurs en termes de débit, les systèmes de communication sans fils se tournent vers des fréquences de plus en plus élevées. La conséquence de cette montée en fréquence est notamment l augmentation des pertes au niveau des éléments conducteurs et donc une diminution de l efficacité globale des systèmes de communication. Dans ces circonstances, les DRA offre de meilleurs résultats par rapport à d'autres familles d'antennes à base d éléments métalliques. De plus, les DRA offrent des pertes diélectriques négligeables, elles sont peu sensibles aux variations de température et s intègrent facilement sur des technologies de fabrication planairesTechnologies such as direct broad cast satellite system (DBSS), Geosynchronous Earth Orbit (GEO) and Low Earth Orbit (LEO) satellite communications , global positioning system (GPS), high accuracy airborne navigation system and a large variety of radar systems demand for high level of antenna performance. Similar is the requirement for upcoming land based wireless systems such as cellular and indoor communication systems that is needed some more specific and additional features added to the antenna to compensate for the deficiencies encountered in system's performance. Though metallic antennas are capable enough to fulfil all the operational requirements, however at very high frequencies and under hostile temperature conditions they are constrained to face certain limitations. To avoid these constraints the performance of Dielectric Resonator Antennas (DRAs) is evaluated and their new applications are proposed. In the thesis, two types of antenna applications are sought :-First is for tracking and satellite applications that needs a larger aperture coverage in elevation plane. This coverage is realized with a good CP purity by proposing two ports dual linearly polarized DRA working at X-band. The DRA is excited by two orthogonal H-shaped aperture slots yielding two orthogonal polarizations in the broadside direction. A common impedance bandwidth of 5.9% and input port isolation of -35 dB are obtained. The broadside radiation patterns are found to be highly symmetric and stable with cross polarization levels -15dB or better over the entire matching frequency band. The maximum measured gain is found to be 2.5dBi at 8.4 GHz.- The 2nd type of antenna is a dual pattern diversity antenna to be used in the Body Area Network (BAN) context. This antenna combines a slot loop and DRA yielding broadside and end-fire radiation patterns respectively. Based upon the feeding techniques, the DG antenna is further divided into two categories one with planar feeds and the other with non-planar feeds (slot loop excited by planar CPW but DRA excited by vertical monopole) .Both types are successfully designed and measured upon body when configured into different propagation scenarios. The non-planar feeds antenna allows wider common impedance bandwidths than the planar feeds (4.95% vs 1.5%).In both cases, a maximum value of DG=9.5dB was achieved when diversity performance tests were carried out in rich fading environments. This value is close to the one (10 dB) theoretically reached in a pure Rayleigh environment and was obtained with efficiencies of 70% and 85% for the slot loop and the DRA respectively. Therefore, we conclude that these antennas could be used on the shoulders or the chest of professional clothes (firemen, policemen, soldier) where full planar integration is not a key issue but where the communication must be efficient in harsh environments and for various gestures, positions and scenariosPARIS-EST-Université (770839901) / SudocSudocFranceF

Circularly polarised planar antenna excited by coplanar waveguide feedline

International audienceA circular patch antenna fed by a coplanar waveguide (CPW) line is proposed to obtain circular polarisation (CP). The CP results from the combined excitation of the patch by an inclined slot (integrated in the CPW feedline) and the CPW feedline termination. The asymmetrical characteristics of the excitation involve the excitation of both the odd and the even modes in the CPW line

CPW-fed patch antenna with switchable polarization sense

This paper presents the design and development of a CPW-fed microstrip patch antenna with polarization reconfigurability (RHCP/LHCP). The basic antenna is a circular microstrip antenna excited by a CPW-fed diagonal slot and a CPW open end. First, experimental and simulated results are presented for the passive antenna. Then, an active antenna using beam-lead PIN diodes to switch the polarization sense is proposed. Simulations are presented including electrical parameters for the diode modeling. The deviation between simulated and experimental results is finally discusse

Reconfigurable circularly polarized antenna for short-range communication systems

This paper describes the design rules of a compact microstrip patch antenna with polarization reconfigurable features (right-handed circular polarization (CP)/left-handed CP). The basic antenna is a circular coplanar-waveguide (CPW)-fed microstrip antenna excited by a diagonal slot and the CPW open end. This device is developed for short-range communications or contactless identification systems requiring polarization reconfigurability to optimize the link reliability. First, experimental and simulated results are presented for the passive version of the antenna excited by an asymmetric slot. A reconfigurable antenna using beam-lead p-i-n diodes to switch the polarization sense is then simulated with an electrical modeling of the diodes. Finally, the efficiency reduction resulting from the diode losses is discussed

Improved Nonlinear Model Implementation for VCSEL Behavioral Modeling in Radio-Over-Fiber links

Open Access provided by `Alma Mater Studiorum - Università di Bologna' within the CRUI CARE AgreementInternational audienc

BAN antenna design using ferrite polymer composite

Wearable antennas are an integral part of body area networks (BAN). Antenna design for BAN applications is a challenging task since the antennas have to be small, efficient and must not be affected by the wearer's body. This makes isolation of antenna a matter of importance. Ferrites form an opaque media for microwave at the ISM frequencies and hence it could be used for the isolation of antenna from surroundings. Thin polymeric ferrite sheets are used to reduce body influence in BAN perspective

Compact antennas for wireless communications and terminals: theory and design

Compact Antennas for Wireless Communications and Terminals deals with compact microwave antennas and, more specifically, with the planar version of these antennas. Planar antennas are the most appropriate type of antenna in modern communication systems and more generally in all applications requiring miniaturization, integration and conformation such as in mobile phone handsets.The book is suitable for students, engineers and scientists eager to understand the principles of planar and small antennas, their design and fabrication issues, and modern aspects such as UWB antennas, reco

New designs of microstrip antennas integrating switching capabilities

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A switchable CPW-fed slot antenna for multifrequency operation

International audienceA CPW-fed slot antenna including pin diodes for multifrequency operation within a frequency octave and more is presented. The use of GaAs beam-lead pin diodes limits the influence of the parasitic resistance and reactance presented by surface mount diodes. The simplicity of the structure results in a simplified and compact biasing circuit