Y. Cailloce

University of Limoges, Limages, Limousin, France

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Publications (15)2.25 Total impact

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    ABSTRACT: A metallic multi-feed EBG structure operating in Ka band [29.5-30 GHz] is presented which is used to feed a reflector for Ka-Band space applications. The feed has been simulated and real filters have been used in order to retrieve radiation characteristics which were disturbed by the coupling. Finally the feed was used to illuminated a reflector and characterize the coverage. C/I ratio higher than 1 ldB have been obtained.
    Antennas and Propagation Society International Symposium (APSURSI), 2010 IEEE; 08/2010
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    ABSTRACT: A new simplified methodology for the design of microwave cavity filters has been presented. The presented work is based on the optimization of Belevitch polynomials and inspired from the Simplified Real Frequency Technique (SRFT). One can bypass the use of computationally expensive circuit simulation softwares which are used to optimize the lumped element circuit model of the cavity filters. The procedure is applied for the design of filters for a multi-feed filter-antenna subsystem for space application.
    Microwave Symposium Digest (MTT), 2010 IEEE MTT-S International; 06/2010
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    ABSTRACT: This paper presents an analysis of different multi-feed EBG solutions, in order to choose the best one which provides overlapped apertures and promises good functioning as a reflector focal array. Two main structures will be studied: the matched and unmatched antenna. Both structures present different kinds of interference and coupling between feeds which disturb the performances of the antenna, especially the radiation. That is why suited filtering functions for each solution will be studied in order to isolate feeds and reconstruct the disturbed radiation. The investigation of all structures and their required filtering functions will lead us to the final promising solution which is the matched multi-feed EBG antenna.
    Antennas and Propagation (EuCAP), 2010 Proceedings of the Fourth European Conference on; 05/2010
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    ABSTRACT: This paper is dedicated to the design of a multi-feed matched EBG antenna, providing overlapped beams, as a reflector focal array for Ka-band space applications. The architecture must ensure the coverage of Europe through 40 spots "Agora mission proposed by CNES" with a 4x reuse scheme (2 linear polarizations and 2 frequency channels). As a first step, the EBG antenna will be studied in mono-feed configuration. Then, the simulation of the multi-feed EBG antenna will show us its suffering from the mutual coupling between feeds which disturbs the radiation. Once the S-parameters of the multi-feed antenna are extracted, suited filters will be connected to the antenna in order to isolate channels and reconstruct the radiation. Finally, the whole system (EBG antenna illuminating a reflector) will be studied in order to characterize the coverage.
    Antennas and Propagation (EuCAP), 2010 Proceedings of the Fourth European Conference on; 05/2010
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    ABSTRACT: This letter presents a first step toward the design of an enhanced multifeed EBG structure that serves as a focal-plane array for a Ka-band reflector for space applications in the 29.5-30-GHz band. The desired Earth coverage is the starting point for the antenna design. As shown in this letter, significant coupling can deteriorate the performance of the multifeed EBG antenna. In order to demonstrate this, the results are compared to those of the single-feed reflector antenna. Filters are then connected to the multifeed antenna ports to control the coupling in a constructive way and obtain good radiation characteristics. Finally, the global feed architecture (EBG structure + filters) is used to illuminate a reflector antenna in order to characterize the antenna performance (C/I ratio, EoC gain).
    IEEE Antennas and Wireless Propagation Letters 02/2010; · 1.67 Impact Factor
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    ABSTRACT: Direct radiating arrays ('DRA') have been proven to be an interesting solution for reconfigurable multibeam transmit antennas, as spreading naturally the RF power to be radiated over the whole aperture, and avoiding cold redundancies thanks to graceful degradation. DRA are in general designed following two main constraints : (1) Antenna diameter is determined by directivity and isolation specifications (2) Grid lattice is constrained by grating lobe rejection outside a given domain (typically outside the Earth, for geostationary satellite antennas considered here) As high directivity beams are mostly required, adding these two constraints leads to a prohibitive number of antenna elements (so of active chains). In order to reduce the number of active chains without affecting antenna pattern characteristics, two solutions are studied here : (1) Array thinning, relies on suppressing part of the radiating elements in the regular grid lattice, (2) Non regular aperture sampling consists in dividing the radiating aperture into non-regular subarrays. Industrial constraints lead to gather small identical elements in rectangular groups with various size. The basic elements are small enough to avoid any grating lobe on the Earth disk; as the 2<sup>nd</sup>-step aperture meshing (by non-regular groups) is non- periodic, no other grating lobes appear on the Earth. Various kinds of mathematical algorithms have been compared for both these arraying methods. They are classified in 2 main categories: a) part I presents so-called "global optimisation algorithms based on random searching": 'genetic' algorithm and 'simulated annealing' are assessed to perform array thinning and subarray division. As a result, such algorithms are well- suited to array thinning, but not to gathering elements in non-regular groups, providing good performances for all numerous beams; so we went to a new category of much different methods b) part II presents a new analytical method, built especially f- - or this problem by UPS/MIP. It associates: (1) an optimised choice of the cost function, able to warrant convergence of a gradient-type method (2) combining solutions found for each beam in a single power distribution on the aperture is performed using the "singular value decomposition" (SVD) method (3) then the obtained distribution is sampled into amplitude values that can be provided by gathering elements by 1, 2, 3, or 4. And the best rectangles arrangement is found in an iterative process using "topologic gradient" method. A clever association of these various steps leads to a non-regular subarrays distribution saving nearly 50% of the initial elements number, while complying for all beams with typical requirements on gain and isolation, and using equal-power feeding, so better efficiency and lower cost for a single amplifiers class.
    Antennas and Propagation, 2007. EuCAP 2007. The Second European Conference on; 12/2007
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    ABSTRACT: The objective of this paper is to present in progress developments on reconfigurable antennas using the MEMS technology.
    Antennas and Propagation, 2007. EuCAP 2007. The Second European Conference on; 12/2007
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    ABSTRACT: Today's satellite communication systems operate mainly in C and Ku frequency bands. They are characterized by broad regional coverages, relatively low satellite gain, EIRP and G/T, and modest data rates. Multibeam payloads and frequency re-use, associated to large bandwidth are the concepts that actual generation communication systems use to palliate these shortcomings.
    01/2007;
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    ABSTRACT: Micromachining and microelectromechanical systems (MEMS) technologies can play a key role in miniaturization of satellite antenna front-ends. Alcatel Alenia Space France has demonstrated for the first time the operation of a V band integrated active feed combining 3D stacking concepts and micromachining technologies. The realized integrated module size is 35 times 35 mm<sup>2</sup> with a thickness of 7 mm including miniaturized DC and RF connectors. In this paper, we present the latest test results obtained on this MEMS based active antenna
    Microwave Conference, 2006. 36th European; 10/2006
  • O. Lafond, M. Himdi, O. Vendier, Y. Cailloce
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    ABSTRACT: This paper deals with an H-shaped slot etched in a thick ground plane to feed multilayer antenna arrays. This study takes place under the European MIPA project 1, which concerns an antenna prototype that is part of a Q-band (50-GHz) one-feed-per-beam antenna reflector. In millimetre waves, it is highly required to separate active layers (MEMS, MMIC, and so on) and radiating elements in order to avoid electrical spuriousness generated by coupling radiation. This separation is done with a very thick metallic support (2 mm). Moreover, this thick ground plane is important with regard to the thermal dissipation aspect. With this aim, the authors present an original feed of antenna array via an H-shaped thick-slot transition. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 44: 24–29, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20536
    Microwave and Optical Technology Letters 11/2004; 44(1):24 - 29. · 0.59 Impact Factor
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    ABSTRACT: An original new design of microwave structure for integrating filter and antenna functions on a single device is presented. The structure is composed of a partially metallized dielectric plate enclosed in a parallelepipedic cavity. This topology allows a high integration in a planar environment type, and is suitable for high frequency filtering and power applications. In order to validate the multilayer radiant filter concept, an open two-pole filter using two superposed cavities coupled by a metallic iris is presented. Its filtering and radiating functions are optimized at the same time to present some required electrical performances. Moreover, to show the variety of uses of the antenna, two examples are described. The first one presents a coupled array of two radiant filters, and the second one an antenna with circular polarization radiation
    Microwave Symposium Digest, 2001 IEEE MTT-S International; 02/2001
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    ABSTRACT: A dielectric resonator device is proposed for high-speed data communication systems. The structure is composed of a partially metallized dielectric plate enclosed in a parallelepipedic cavity. This topology allows a high integration in a planar environment type. This structure, easily manufactured, is suitable for high frequencies filtering and powers applications. In order to realize some radiant n-pole filters without tuning, an opened two-pole filter using two superposed cavities coupled by a metallic iris is presented. Its filtering and radiation functions are optimized in the same time to present some required electrical performances.
    Microwave Conference, 2000. 30th European; 11/2000
  • Y. Cailloce, G. Caille, I. Albert, J.M. Lopez
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    ABSTRACT: This paper deals with direct radiating array pattern simulations in Ka band (transmit Tx and receive Rx). The DRA is used to generate a multiple beam coverage from a geostationary satellite to provide broadband services to fixed or mobile users in a local Earth region. Particular emphasis is placed on the antenna optimization in order to reduce the number of radiating elements with respect to the requirement. We have selected a typical mission corresponding to a precise ITU filing
    Phased Array Systems and Technology, 2000. Proceedings. 2000 IEEE International Conference on; 02/2000
  • H. Legay, Y. Cailloce, L. Scialino