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In this paper, basic MEMS switching networks fabricated on alumina substrate have been presented. Such devices could be used to design multiple input-output switching matrixes able to select and steer RF signals to satellite smart antennas for example. For their low loss, low power consumption and high linearity, MEMS switches appear to be particularly well suited for these applications. This paper...
This paper presents two new designs of dual frequency coplanar waveguide (CPW)-fed double folded slot antennas. This includes both conductor backed and non-conductor backed CPW that radiate into a half space or full space, respectively. An important advantage of these antennas is that each is self-matched to 50 Ω CPW feed line without the need for external matching circuit. This reduces the antenna...
The object of our study is to use photonic band gap structures (PBG) in the conception of materials with specific electromagnetic properties in microwave frequency range: absorbing, scattering or transparent materials. The main domains of applications are Electromagnetic Compatibility or uperstrates of antennas.
In this paper a novel method for the solution of parabolic equation will be presented, whereby its solution of parabolic equation will be expanded by the second order spline basis functions. Then by means of the least square method, the expansion coefficients will be obtained. In comparison with the split step method, the proposed algorithm is more flexible. This method can be used for propagation...
Two small short-circuited antennas of λ0/11 and λ0/8 have been designed and measured. Their respective bandwidths of 120 MHz (2.3 %) and 190 MHz (3.6 %) make them suitable for 4G telephony applications. An array of two miniature antennas has also been built. Its performances show that it is appropriate for MIMO applications.
A new formula is derived for the estimation of signal correlation based on radiation patterns of multiantenna terminals and a power distribution model of the radio channel. The new formula takes into account the correlation between the vertical and horizontal components of the incoming signals in the radio channel. The formula can be used in situations where the properties of the radio channel are...
A microstrip reflectarray is a low profile antenna consisting of an array of radiators illuminated by a feed as shown on Fig. 1. Beamforming techniques and performances have been widely studied to improve spherical wave to plane wave transformation using patches of variable sizes for instance [1,2], or stub loaded patches [3], or variable slots in ground plane [4]. These approaches are based on the...
In this contribution, we apply the mapping between conformal antennas in complex geometries and planar equivalent antennas loaded with complex materials [F. Bilotti, A. Alù, L. Vegni, PIER 47, 1 (2004)] to the case of spherical and spheroidal geometries. Even though the complexity of the problem is not reduced after this rigorous mapping, a generalization of the Method of Lines (MoL) numerical algorithm...
In the IRCOM laboratory, the antenna research team (CREAPE) has designed and built its own Compact Antenna Test Range (CATR). This equipment operates from 8 to 50 GHz for high gain antennas. n this paper, we describe the CATR and its performances are compared with the CNES CATR. The design, the realisation and the validation of the CATR have been made in our laboratory in order to reduce the cost...
Dielectric loaded waveguide filters are extremely attractive for space applications, thanks to the reduction of size and weight that can be achieved using these components. Another remarkable advantage is the high temperature stability and the high quality factor of the recent dielectric materials, allowing in many cases these products to be the optimum choice for the filter realisation in comparison...
Due to specific requirements for automotive applications, the design of an integrated antenna system able to guarantee the connection to several wireless services, i.e. GPS, GSM/GPRS and COSPAS-SARSAT, must be faced as an optimization problem. Starting from electrical and geometrical constraints, the design of the antenna must be faced considering, in addition to usual antenna design procedures, also...
If a suitable parasitic element position in far field of an antenna, it can produce a well-designed null in an arbitrary direction of a general antenna. Using acceptable simplifications, analytical results describe this phenomenon approximately. This method is general for all type of antennas. This method has been used to suppress the pattern of a two-element array antenna. The simulation results...
A design methodology of optimized homogeneous dielectric lens antennas is proposed. The procedure comprises two successive stages. Geometrical Optics (GO) principles are firstly implemented to determine the best lens profile that radiates a specified amplitude-shaped output pattern. Then this GO solution serves as an initial condition to optimize the lens shape using an analysis kernel based on the...
In mobile communications, transmission channel causes significant effects on the signal of mobile users received by the BTS. These changes can degrade the performance of the beamformer. In this paper, undesired effects of the transmission channel on the performance of the LS-CMA based beamformer are investigated both theoretically and through simulations. Investigations of this paper show that the...
The interest to the printed antennas including circular antennas is kept high since long ago. It is explained by several facts such as their low profile, low cost, light weight, etc. Many methods commonly applied in electromagnetic theory have been used in their analysis, starting with empirical methods and finishing with method of moments (MoM) and finite difference time domain methods (FDTD). However,...
A new uni-planar, compact and broadband surface wave launcher fed by a coplanar CPW is introduced. The launcher outperforms its previously reported Yagi-Uda based counterparts in terms of bandwidth, size and robustness. Being so compact in the lateral size allows two launchers to be arranged in a side-by-side configuration that have applications in scanning at a single frequency by means of substrate...
This paper gives an overview of developments and projects in the area of steerable antennas (phased array) at IMST. Through the years, this type of antenna has become a key area within IMST and various projects have been conducted in the past, and are currently ongoing. Phased array antennas incorporate in general active components for beam steering, and have achieved ever more popularity during the...
In this paper, a new type of smart antennas based on EBG material properties, and suitable for base stations deployment is presented. In traditional smart antennas, the beamforming is realized by means of phase shifts between several excited antennas constituting the network. The proposed smart antenna excites only one element and the beam switching is realized by exciting the antennas at different...
Our works presented here consisted in validate a concept of beam scanning used for automotive radar. A 2.45 GHz antenna, used as demonstrator, was designed. The principle is based on Yagi-Uda antennas, with a fed monopole and two loaded parasitic ones. Then, beam scanning is accomplished uniquely by properly switching parasitic loads. Concept, simulations and even experimental results are provided,...
In a recent report [1] we have employed the source scattering-matrix formulation [2] with vector spherical wave functions [3]–[4] to investigate traveling electromagnetic waves on infinite linear periodic arrays of lossless penetrable (magnetodielectric) spheres. It is assumed that either the spheres are sufficiently small that only the dipole scattered fields can be excited, or the frequency is such...
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