Serwis Infona wykorzystuje pliki cookies (ciasteczka). Są to wartości tekstowe, zapamiętywane przez przeglądarkę na urządzeniu użytkownika. Nasz serwis ma dostęp do tych wartości oraz wykorzystuje je do zapamiętania danych dotyczących użytkownika, takich jak np. ustawienia (typu widok ekranu, wybór języka interfejsu), zapamiętanie zalogowania. Korzystanie z serwisu Infona oznacza zgodę na zapis informacji i ich wykorzystanie dla celów korzytania z serwisu. Więcej informacji można znaleźć w Polityce prywatności oraz Regulaminie serwisu. Zamknięcie tego okienka potwierdza zapoznanie się z informacją o plikach cookies, akceptację polityki prywatności i regulaminu oraz sposobu wykorzystywania plików cookies w serwisie. Możesz zmienić ustawienia obsługi cookies w swojej przeglądarce.
The purpose of this work is to design a frequency-scaled monopulse Radial Line Slot Array (RLSA) antenna intended for a space debris detector radar. Firstly, the slots arrangement is designed and optimized by using a global optimization algorithm where the analysis is based on an inhouse Method of Moment algorithm. A Δ pattern prototype is manufactured and tested. Secondly, a monopulse feed based...
Nowadays, the communications links limit the autonomy of unmanned aerial vehicles (UAV). In this paper, a multichannel long-range communication link for UAVs with high quality of service, moderate bandwidth and affordable cost is proposed. This link is deployed by using a second UAV as a communications relay and it provides bidirectional coverage for telemetry and telecommand and a high-capacity downlink...
This paper describes a modular active antenna for satellite communications in the K/Ka band. The application is thought for mobile satellite communications and internet links, mainly for commercial airplanes. The impossibility to build full active antennas, including amplifiers in all the elements, leads to a modular semi active antenna. Here the module is a small subarray with complete phase control...
This contribution provides the design of a microwave phase shifter for active steerable reflectarray devices at microwave frequencies. The device is based on a 3dB hybrid coupler with three of its ports connected to reflective circuits. This reflective circuit is responsible of the phase variation by means of the use of an electrically controllable microwave varactor. More than 360° phase shifting...
This paper is aimed to explain the radiation test in temperature performed on the radiofrequency assembly (RFA) of the Medium Gain Antenna (MGA) of ESA BepiColombo mission. The goal of this mission is to observe and study Mercury and its surroundings in a very demanding and stringent environment in terms of temperature and radiation. The paper presents the measurement set-up for the qualification...
This paper presents a comparison between two different echo reduction techniques applied to one-single cut antenna measurements. These techniques are based on modal filtering and time filtering. The first technique uses a post-processing of the far field one-single cut so as to obtain a modal expansion of cylindrical modes and to cancel the effect of spurious signals. The second one is based on filtering...
This paper presents a review of the time filtering methods to eliminate echo in antenna measurements. Two different methods, FFT and Matrix Pencil, are compared and simulated in a Planar Near Field (PNF) where other effects, such as aliasing, can happen if the simulation is not carefully carried out. Finally both time gating methods are applied to different real measurement of several antennas in...
Different research groups have been working during the last years in different echo reduction techniques applied to antenna measurements, based on spatial, modal or time filtering. Some applications where these methods are usually employed are: outdoor systems, for HF or VHF frequency systems or for small measurement systems where the anechoic material is only placed in front of the AUT. This paper...
A method to reconstruct the excitation coefficients of wide-slot arrays from near-field data is presented. The plane wave spectrum (PWS) is used for reconstruction, and the shape of the field distribution on a wide slot is considered in the calculation of the PWS. The proposed algorithm is validated through the reconstruction of the excitation coefficients of a wide-slot array with element failures...
The design of a 60GHz Radial Line Slot Antenna (RLSA) for compact range communications is discussed in this paper. A taper window was investigated and applied for a uniformly illuminated circular aperture in order to create a uniform field in a specified receiving zone. Predicted results show a good uniformity up to a few meters in the propagation distance, and on a receiving horizontal plane as large...
Radial Line Slot Antenna (RLSA) [1] is an attractive candidate for high gain and low cost circular polarized antennas. During the last decades, there has been an increasing interest in RLSA due to several reasons: the first of them is their simple structure, which makes them suitable for low cost mass production. Furthermore, their low profile allows them to be easily adapted to any surface. Finally,...
This paper studies the operation of Radial Line Slot Antennas (RLSAs) having lossy substrates as waveguide-filled materials. Based on the operating mechanism of the conventional lossless RLSAs, new formulations to optimize the antenna gain are derived theoretically and partly confirm by measurement. As the result, at 32GHz, a 90cm diameter RLSA with material loss factor of 0.014∼0.018dB/mm, about...
A source reconstruction technique for slot array antennas is presented. By exploiting the information about the positions and the polarizations of slots to the Gerchberg-Papoulis iterative algorithm, the field on the slots is accurately reconstructed. The proposed technique is applied to the source reconstruction of a K-band radial line slot antenna (RLSA), and the simulated and measured results are...
This paper presents a reflection suppression technique for far field antenna measurements. The technique is based on a source reconstruction over a surface greater than the antenna itself. To be able to perform the reflection construction the next steps are required: the complete far field antenna pattern is obtained through interpolation of the acquired cuts, the currents are obtained through a holographic...
This paper presents the analysis of the reflections in two kind of spherical far field ranges: one if the classical acquisition where the AUT is rotated and the second one corresponds to the systems where the AUT is fixed and the antenna probe is rotated. In large far field systems this is not possible, but this can be used to the measurement of small antennas, for instance, with the SATIMO StarGate...
In this paper, four new applications of sources reconstruction techniques (also called diagnostic techniques) are presented. First of all, the important information of such techniques will be mentioned, seeing that they are a tool to obtain the extremely near field from the measured data. Depending on the region where these data are taken (near field or far field), the reconstruction method will be...
A cylindrical near field measurement system for huge L-band RADAR antennas has been designed, and it is under construction. The cylindrical near field system consists of a 17 meters tower (15.5 meters linear scanning), placed at a distance between 4 and 7 meters from the centre of the RADAR antenna. The RADAR antenna is placed on its azimuth positioner, and the system must allow the measurement of...
A software for the analysis and design of radial slot antennas excited by one or several coaxial probes is presented. This tool has two main different blocks: analysis and design. The software has been improved with a file input/output options and a graphic display of radiation patterns, impedance, directivity and other antenna parameters. Everything is compiled in C++ for Windows. The second part...
Podaj zakres dat dla filtrowania wyświetlonych wyników. Możesz podać datę początkową, końcową lub obie daty. Daty możesz wpisać ręcznie lub wybrać za pomocą kalendarza.