Multicriteria Optimisation in Weather Routing

The paper presents a new weather routing solution fully supporting multicriteria optimisation process of route finding. The solution incorporates two multicriteria optimisation methods, namely multicriteria evolutionary algorithm (SPEA) and multicriteria ranking method (Fuzzy TOPSIS). The paper focuses on presenting the proposed multicriteria evolutionary weather routing algorithm (MEWRA). Furthermore, it includes some experiment results together with a short description of the assumed ship model

Wideband multibeam arrays of long slots fed by quasi-optical systems

International audienceThis paper summarizes the latest advances on an innovative, broadband multibeam antenna, proposed for satellite communications by the Institute of Electronics and Telecommunications of Rennes (IETR), in the framework of a collaborative research with the French Space Agency (Centre National d'Iîtudes Spatiales). The antenna comprises an array of long slots, parallelfed by a corporate feed network of parallel plate waveguides. An integrated quasi-optical beamformer, illuminated by a single horn or by a focal array of horns, excites the feed network. The beam scanning can be achieved both mechanically and electronically. The numerical models developed for the analysis and design are reviewed. The experimental results presented for a Ka-band design demonstrates the wideband, wide-angle scanning performance of the proposed architecture. Finally, future research lines for achieving circular polarization are projected. The proposed antenna concept is particularly suitable for high throughput ground terminals on moving platforms. © 2017 Euraap

Review on wideband and compact CTS arrays at millimeter waves

International audienceIn this paper, three state-of-the-art parallel-fed continuous transverse stub (CTS) arrays are presented. They operate at various frequency bands ranging from 20 GHz up to 86 GHz. The multiple capabilities of this architecture, such as side-lobe level reduction, active beam switching, and wideband operation with an ultra-low-profile, are here reviewed. Moreover, the suitability of the antenna concept for multiple fabrication technologies is demonstrated. The performance and key design solutions of three prototypes manufactured using milling techniques, low-temperature co-fired ceramic and printed circuit board technology are showcased. © 2021 IEICE

Imaging system fed by a quasi-optical beam-forming network for Ka-band satellite applications

International audienceA quasi-optical system in Substrate Integrated Waveguide (SIW) technology is proposed to feed the primary array of an imaging system for satellite applications in Ka-band. An in-house Physical Optics (PO) tool is used for the complete antenna design reducing the phase aberrations of the imaging system and at the same time improving the Earth coverage by the Satellite. Measurement results validate the overall approach. © 2016 IEEE

A Novel Dual-Polarized Continuous Transverse Stub Antenna Based on Corrugated Waveguides - Part II: Experimental Demonstration

International audienceWe present the experimental validation of the dual-mode, polarization-agile parallel-fed continuous transverse stub (CTS) antenna architecture introduced in Part I of this two-part paper. The Ka-band dual-mode CTS array described in Part I is characterized when it radiates in horizontal and vertical polarization. To this end, it is combined with two different quasi-optical beamformers operating in a quasi-transverse electromagnetic (quasi-TEM) and in a quasi-transverse electric (quasi-TE 1 ) mode, respectively. The scanning capabilities of both multibeam antenna systems are demonstrated. The CTS array and its feed network comprising corrugated parallel-plate waveguides (CPPWs) are fabricated by additive manufacturing. Measurements show that the dual-polarized CTS antenna works between 29 and 32 GHz in a field of view of about 45°, achieving a peak gain of 31.3 dBi and very low cross polarization. These promising results pave the way for the realization of dual-circularly polarized beam-scanning antennas with application to broadband and compact Ka-band ground terminals

Recent and future research trends in planar multi-beam antennas in the millimeter wave range at IETR-France

International audienceA review of some flat multi-beam antennas developed at IETR during the last 5 years (2010-2015) is reported. These antennas are based on quasi-optical and circuit-based beam forming networks (BFNs). The enhanced scanning capabilities of the proposed solutions will be shown. In addition, some antennas integrate antenna functions like monopulse techniques to enhance the angular resolution for tracking applications. The main concepts and features of the developed antennas will be reported. These antennas operate in different frequency band in the millimeter wave range and are realized with different fabrication processes. © 2016 IEICE

Analysis of Circularly-Polarized CTS Arrays

International audienceThis paper presents an efficient analysis method for a novel continuous transverse stub (CTS) antenna. As opposed to state-of-the-art CTS antenna designs, the proposed architecture achieves circular polarization using a single CTS array and without any polarization converter. The structure consists of long radiating slots/stubs fed by over-moded parallel-plate waveguides. More precisely, the transverse electromagnetic (TEM) mode and the first transverse electric (TE1) mode of the feeding waveguides are used to generate a circularly-polarized field. The array is analyzed using a spectral mode-matching method. First, the active reflection coefficient of the infinite array is derived in closed form. A windowing approach is then adopted to compute the radiation patterns of finite-size arrays. Numerical results obtained with this method are in excellent agreement with full-wave simulations, carried out with a commercial software. The performance of this class of CTS antennas has been investigated using the developed model. It is theoretically demonstrated that the proposed array can be designed to attain an axial-ratio (AR) lower than 3 dB over a 52.9% relative bandwidth at broadside. Furthermore, the active input reflection coefficient is lower than -10 dB over a 40.8% relative bandwidth when the array steers its main beam at and#x03B8; 0 = 45and#x2218;. This solution is an attractive candidate for next generation satellite communication terminals. IEE