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International audienceWe present in this letter the study of a multibeam antenna for telecommunication networks by using cylindrical electromagnetic band-gap (EBG) structures. The EBG structure behaves as a partially reflecting surface (PRS) and enhances the directivity of a simple radiating source. We begin by presenting the principle of the multibeam antenna, and then we present a first version, conceived to operate in WiMAX band [5.45.7] GHz. Simulation results of this antenna will show us that the strong mutual coupling between the different excitation sources of the EBG structure badly influences its performance. In order to reduce the mutual coupling, metallic walls are inserted between the excitation sources. Moreover, excitation sources have been changed to improve the radiation performance of the antenna. A prototype of the final antenna is fabricated to validate our simulation results, and the measurements results are compared to the simulated ones

We present the design of a multibeam reflector antenna fed by a multifeed dual-band electromagnetic band gap (EBG) antenna to achieve a high-gain multispot coverage for space applications. First, we design a dual-band EBG antenna in monofeed configuration. This antenna is composed of double-layer frequency selective surfaces (FSSs) arranged in the longitudinal direction and a square horn as a feed. Then, the same antenna in multifeed configuration is studied, and the results are compared to those obtained in monofeed configuration in order to emphasize the problem of coupling, generally encountered in multifeed configuration. Consequently, filters are used in order to reduce the parasitic interferences and obtain good radiation characteristics. As shown in this paper, the same EBG phase center is obtained in both frequency bands. Finally, we have studied the whole system composed of the offset reflector and the multifeed EBG dual-band antenna. An edge of coverage (EOC) gain higher than 42 dBi and sidelobes levels lower than −18 dBi are obtained over all spots.

This article presents a new method to realize sectoral antennas for base station by incorporating metallic partially reflecting surface (M‐PRS).The main idea consists in inserting simple radiating elements, as patches, inside a Fabry‐Perot cavity resonator. This consists of a ground plane, where the feeding system rests covered by a rectangular M‐PRS. A patch array is used as a feeding structure to enhance directivity and radiation bandwidth. A rectangular M‐PRS antenna for the uplink UMTS frequency band [1.92–1.98 GHz] working in vertical polarization is designed, and its performances are disclosed. Finally, a prototype is realized and the experimental measurements are compared to the simulated ones. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:990–994, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25044

Transmit-arrays (TAs) are a popular cost-effective solution for high-gain antennas at millimeter waves (mmW). The design of these antennas relies on the fine tuning of the subwavelength unit-cells that compose the aperture. The intricacy of the unit-cells increases as new features are implemented, such as dual-band operation and wide-angle beam steering, making this antenna even more computationally challenging. In this work, a high gain (25 dBi @ 20 GHz and 28 dBi @ 30 GHz) multiscale Ka dual-band TA for beam-steering applications is analyzed using a massively parallel implementation on multicores clusters of the Finite Element Tearing and Interconnecting method, with a two Lagrange Multiplier (FETI-2LM) technique. The main contribution of this work is the implementation of 3D non-periodic grids with sub-domains of different scales, that is suitable for proper modelling of different regions of the antenna (horn feed, lens cells, air region). An automatic batch file procedure is proposed for the TA meshing, allowing the limited set of constitutive unit-cells of the TA to be meshed separately. Additionally, we are using a block-Krylov strategy to efficiently capture the TA beam-steering capability, without restarting from scratch the interface problem for each feed position. Since other Finite Element Method (FEM) results were not accessible due the size of the problem, the FETI-2LM numerical results provided in this work are compared with other MultiLevel Fast Multipole Method (MLFMM) [1] and Transmission Line Modeling Method (TLM) [2] of CST Microwave Studio solvers, as well as with the measured results of the corresponding Ka dual-band prototype. The computational infrastructure has been used only a fraction of its capacity. Therefore, a much higher gain design (40 dBi) can be assessed, opening a new realm of applicability of TAs in the space segment usually occupied by reflector-based solutions.