Monolithic Microwave Integrated GaAs Electromagnetically-Coupled Antenna

Monolithic antenna on GaAs to be used in miniature active sensors is presented. After a first study of technological processes and the characterisation of various substrates in K-band, the feasibility of an antenna, operating in K-band, electromagnetically-coupled and integrated on GaAs by monolithical realisation, has been demonstrated. A low profile (1mm) and wide bandwidth (2.3 GHz around 25 GHz) antenna is obtained

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

Wideband compact antenna for K-band applications

A compact coupled microwave active antenna is presented. This antenna is proximity fed, and consists of a square radiating element array on a polymer dielectric layer. The compactness of the antenna is obtained through technological optical processes and the parasitic patch phenomenon which increases the bandwidth

Energy Harvesting with 2.45 GHz Rectenna for urban application

This paper describes the conception of a 2.45 GHz rectenna for energy harvesting application. Electromagnetic simulations have been carried out using Computer Simulation Technology software. The enhancement of the simulated output DC voltage is obtained with resonant circuit and Cockroft Walton boost (containing four zero bias diodes) for a sinusoidal input voltage. The simulated proposed rectenna with single zero-bias diode and RF-DC boosting circuit have been realized and measured inside an anechoic chamber. The behavior of measured plots is in accordance with the simulated ones. The simulated RF-DC boosting rectenna enhanced the output DC voltage up to 140 mV for 1 μW/cm 2 power density

Single-fed circularly polarized dielectric resonator antenna using a uniaxial anisotropic material

A Dielectric Resonator Antenna operating in circular polarization is presented. The proposed antenna is formed by a uniaxial anisotropic dielectric and a ground plane. The optimization of the permittivity tensor and antenna dimensions is performed both theoretically and numerically using an Eigen mode analysis in Ansys HFSS. A good agreement is obtained for the resonant frequencies and quality factors of the different modes. The uniaxial anisotropic DRA radiates two degenerate orthogonal modes, TE111x and TE111y, with equal amplitudes and 90° phase difference in order to achieve circular polarization. An impedance bandwidth of 9.8% is accomplished and a broadside radiation pattern with left-hand circular polarization (LHCP) is achieved in simulation. Furthermore, an Axial Ratio (AR) of 0.06 dB at 2.45 GHz and a 3-dB AR bandwidth of 2.04% are obtained. The maximum simulated directivity is equal to 6.56 dBi

Circularly polarized microstrip antenna coupled on an asymmetrical cross coplanar slot

A new compact multilayer planar structure is proposed to obtain circular polarization (CP) for the direct broadcast satellite (DBS) reception applications. The use of a circular planar antenna fed by asymmetrical coupling slot integrated on a coplanar−waveguide (CPW) feed line allows to achieve a 3dB axial ratio (AR) bandwidth greater than 2% and a −10dB reflection coefficient bandwidth greater than 20%. The antenna design is presented and the comparison between simulations and experimental results are done

LMDS base station antenna design

The design of a feed network for a 24 x 2 stratified linearly polarized patch array is presented in this article. This design is a candidate for an LMDS Base Station antenna and complies with ETSI Standard requirements such as polarization, bandwidth, gain, -3 dB beamwidths and Side lobe levels. The feed network has been designed to produce appropriate unequal power excitation for each patch and a match condition at the feed point. Unequal distribution of the power improves the side lobe level. From simulation, the array antenna yields -23 dB return loss in the LMDS band, narrow -3 dB beamwidths of 2.9° and 46° in the elevation plane and azimuth plane respectively, high gain of 23 dB and 7.5 % bandwidth satisfying with ETSI Standard

Antennes intégrées multicouches. Caractérisation diélectriques et applications

Des procédés de réalisation d’antennes micro-ondes en technologie micro-rubans multicouches sont décrits. La gamme de fonctionnement des antennes s’étend jusqu’à 24 GHz. Une méthode originale de caractérisation à 24 GHz des propriétés diélectriques de la couche émissive de l’antenne est exposée. Un procédé innovant de réalisation de films diélectriques destinés à la conception d’antennes actives est exposé, ainsi que sa caractérisation de 2.45 à 24 GHz

A multilayered coil antenna for ingestible capsule : near field magnetic induction link

A compact multilayered stacked ingestible coil antenna is investigated for medical systems. The inductive link, comprising a 5-layer transmitter coil antenna and a 3-turn receiver spiral coil, is modeled through a tissue-simulating liquid modeling the human body. The diameter and the thickness of the transmitter coil are respectively equal to 1 cm and 5 mm, while the dimensions of the receiver coil are equal to 7 × 8 cm 2 . The variations of the position and the orientation of the capsule antenna are taken into account to evaluate the coupling response between the two magnetically coupled coils. We found that the inductive link presents an attractive option for improving the lifetime of ingestible capsules

A bird-cage coil for MRI studies of unsatureted granular materials

Magnetic Resonance Imaging (MRI) is a powerful and non-invasive technique that can be used to reveal useful information about different types of materials. During an MRI experiment a magnetic resonance signal is induced (according to Faraday’s law of induction) in a device called “probe”. MRI probes are simply near field antennas designed in a specific way in order to produce a homogeneous magnetic field at a specific frequency in the region of interest. MRI is a strong technique to study unsaturated granular materials. However, it suffers from a significant drawback, that is inherent small signal-to-noise ratio. To overcome this problem the probe used for a specific MRI experiment must be optimised. In this work a bird-cage probe operating at 21.3 MHz, optimised to study unsaturated granular materials under shear stress as well as some experimental results will be presented