Etude et réalisation d'une antenne oscillatrice à 40 GHz

L'objet de cet article est l'étude de l'association d'une antenne multi-couche avec un oscillateur. Les antennes imprimées multi-couche sont favorables à l'intégration de composants actifs. Habituellement, les oscillateurs sont conçus à partir de composants actifs tels que les transistors ou les diodes. L'antenne oscillatrice imprimée est une solution technologique pour la réalisation de systèmes de communication légers et faible coût. Un point important est la possibilité de changer la fréquence d'émission de l'antenne pour permettre des communications numériques. Une méthode de conception est présentée et les performances à 40 GHz d'un prototype sont mentionnées afin de valider le fonctionnement en bandes millimétriques de l'antenne oscillatrice imprimée

Superstrate Antennas for Wide Bandwidth and High Efficiency for 60 GHz Indoor Communications

International audienc

A 2D Synthetic Aperture Radiometry Demonstrator by Switching Strategy at X band

International audienceThe broad topic of the presented paper consists in the research on novel methods in the field of microwave imaging, in particular the so-called passive microwave / millimeter-wave imaging, which is also referred to radiometric imaging. This study focuses on proximity range applications such as concealed objects detection, human body screening, etc. The aim is to design a low cost and compact fully electronic passive imaging system suitable for short-range 2D imaging applications, and study the necessary devices for the implementation of a complete demonstrator. In this study, a new approach based on the use of a switch sub-matrix strategy has been adapted into a complete antenna system at X band. The main objective of this prototype is to validate this approach experimentally. Image quality is examined by using the interferometric aperture synthesis technique and G-matrix calibration imaging algorithms. The spatial resolution is measured by using the emission from noise source and is compared with theory

A synthetic aperture interferometric radiometer test at X-band for potential improvements at W-band

International audienceThe broad topic of the presented paper consists in the research on novel methods in the field of microwave imaging, in particular the so-called passive microwave / millimeter-wave imaging, which is also referred to radiometric imaging. This study focuses on proximity range applications such as concealed objects detection, human body screening, etc. The aim is to design a low cost and compact fully electronic passive imaging system suitable for short-range 2D imaging applications, and study the necessary devices for the implementation of a complete demonstrator. In this study, a new approach based on the use of a switch sub-matrix strategy has been adapted into a complete antenna system at X band. The main objective of this prototype is to validate this approach experimentally. Image quality is examined by using the interferometric aperture synthesis technique and G-matrix calibration imaging algorithms. The spatial resolution is measured using the emission from noise source and compared with theory

A 2D Synthetic Aperture Radiometry Demonstrator by Switching Strategy at X band

International audienceThe broad topic of the presented paper consists in the research on novel methods in the field of microwave imaging, in particular the so-called passive microwave / millimeter-wave imaging, which is also referred to radiometric imaging. This study focuses on proximity range applications such as concealed objects detection, human body screening, etc. The aim is to design a low cost and compact fully electronic passive imaging system suitable for short-range 2D imaging applications, and study the necessary devices for the implementation of a complete demonstrator. In this study, a new approach based on the use of a switch sub-matrix strategy has been adapted into a complete antenna system at X band. The main objective of this prototype is to validate this approach experimentally. Image quality is examined by using the interferometric aperture synthesis technique and G-matrix calibration imaging algorithms. The spatial resolution is measured by using the emission from noise source and is compared with theory

Technological Process to Control the Foam Dielectric Constant Application to Microwave Components and Antennas

International audienceA technological process to control the foam dielectric constant, an important issue for the design of microwave components and antennas, is described. For that purpose, the use of different commercial foam materials has been considered. This kind of foam substrate is made of original material (Polyvinyl chloride, resin, and ...) into which gas is injected. Therefore, the dielectric constant of such foam is close to one. It can be increased by expelling the gas out of the foam material. The authors are presenting the technological process used to expel the gas by pressing a foam slab at relatively low temperature (90 °C). Because of this technological process, the dielectric constant variation can be controlled by the ratio between the initial and final slab thickness. It holds a great interest for the design of microwave antennas and circuits. Indeed, the dielectric constant inside gradient index lenses (Luneburg, Maxwell fish-eye, and Fresnel lenses) must follow a particular law to obtain the desired radiation capabilities. The results of materials characterization are presented to validate the technological process. Foam-based antennas and components are also shown to illustrate the interest of the process

Investigating the Influence of Rotating Steel Platform in the RCS Measurement of Vehicles At 22-26 GHz for Automotive Radar Application

International audienceThis paper investigates the influence of rotating applications, such as ACC (Adaptive Cruise Control) or FCW steel platform in the RCS (Radar Cross Section) measurement of (Forward Collision Warning). vehicles at 22-26 GHz for automotive radar application. Across several measurement steps, we compare different RCS measurement results in order to eliminate the undesired RCS contribution caused mainly by the rotating steel platform. We demonstrate that when it is difficult or impossible to use microwave absorbers on the steel platform, an alternative scan (symmetry of vehicle) of target vehicle, the VUT should method can be applied. Finally, with the help of 2D radar image be positioned on a rotating steel platform. The RCS measurement configuration could be described as follows. As in a real road cruising situation, we carry out RCS measurements in outdoor conditions. Secondly, considering the weight of VUT, and the need of a continuous 180° azimuth post processing, we can also identify and separate the RCS contribution of each element (vehicle, steel platform, ground/multipath/clutter) in the hologram image, and therefore obtain the pure RCS distribution of the tested vehicle

Foam Based Luneburg Lens Antenna at 60 GHz

International audienceAn innovative technological process is investigated to easily manufacture inhomogeneous Luneburg lenses. A unique foam material is drilled and pressed to achieve the different dielectric constant needed to follow the index law inside the lens. The performance of such 60 GHz antenna is described and the antenna prototype is measured in terms of gain and radiation patterns. The results show a good efficiency (60% with a directivity of 18-19dBi) and demonstrate the feasibility of this kind of Luneburg lens, through the use of a simple technological process. The lens with a diameter of 56mm and a thickness of 3mm operates in the 57-66 GHz bandwidth. The magnitude of S11 parameter is under -10dB in the whole bandwidth and an half-power beamwidth of 5° and 50° in H-plane and E-plane respectively is reached

Investigating the Influence of Rotating Steel Platform in the RCS Measurement of Vehicles At 22-26 GHz for Automotive Radar Application

International audienceThis paper investigates the influence of rotating applications, such as ACC (Adaptive Cruise Control) or FCW steel platform in the RCS (Radar Cross Section) measurement of (Forward Collision Warning). vehicles at 22-26 GHz for automotive radar application. Across several measurement steps, we compare different RCS measurement results in order to eliminate the undesired RCS contribution caused mainly by the rotating steel platform. We demonstrate that when it is difficult or impossible to use microwave absorbers on the steel platform, an alternative scan (symmetry of vehicle) of target vehicle, the VUT should method can be applied. Finally, with the help of 2D radar image be positioned on a rotating steel platform. The RCS measurement configuration could be described as follows. As in a real road cruising situation, we carry out RCS measurements in outdoor conditions. Secondly, considering the weight of VUT, and the need of a continuous 180° azimuth post processing, we can also identify and separate the RCS contribution of each element (vehicle, steel platform, ground/multipath/clutter) in the hologram image, and therefore obtain the pure RCS distribution of the tested vehicle