Thierry Monédière

An electromagnetic bandgap resonator antenna

This paper introduces a new explanation of the electromagnetic bandgap (EBG) material properties using the study of the EBG structures in the frequency domain and reciprocal space. Once the behavior of such a material is understood, the properties of the EBG are used in order to make an EBG antenna. The antenna is realized with dielectric EBG rods. Its directivity is increased compared to a simple patch antenna. Such a device allows us to obtain a high gain with a very thin structure.

Enhancement of gain and radiation bandwidth for a planar 1-D EBG antenna

This letter describes a technique to increase the radiation bandwidth and the gain of a classical planar electromagnetic band gap (EBG) antenna. Those two parameters are relative to the EBG material but also to the excitation, this second characteristic is studied here. The principle is to excite the EBG structure with several sources (instead of a single one classically). The performances depend on the number of sources and their spacing. Directivity and radiation bandwidth can be increased dramatically with few sources.

Circularly polarized metallic EBG antenna

This letter describes the concept and the realization of a directive and circularly polarized antenna using an electromagnetic band gap material whose circular polarization is generated by the structure itself. Experimental and simulated results are presented for an antenna operating at 5GHz.

Compact and Multiband Dielectric Resonator Antenna With Pattern Diversity for Multistandard Mobile Handheld Devices

A compact multiband antenna system using a dielectric resonator antenna (DRA) is presented in this paper. Designed to be integrated in a tablet, it is not only heavily miniaturized (λ0/15×λ0/38×λ0/94 at 800 MHz), but also able to cover three frequency bands for different wireless applications (DVB-H, WiFi and WiMAX). Since a reconfigurable radiation pattern can result in an improved quality and reliability of wireless links, two DRAs have been integrated to implement this feature on the three frequency bands. These improvements are demonstrated by the presentation of the correlation coefficient and the effective diversity gain, both measured in a reverberation chamber. The experimental measurements are in very good agreement with the simulated ones. Good overall performances are obtained, and the requirements of all three applications are perfectly met. Moreover, the antenna operative frequencies are independent of the ground plane dimensions, making this system a very good candidate for all kinds of mobile devices.

Dual-Band EBG Resonator Antenna Using a Single-Layer FSS

This letter presents a new design for electromagnetic bandgap (EBG) resonator antennas allowing to create dual-band structures, thus, making it possible to circumvent the problem of their narrow bandwidth. The geometry and working of the antenna are detailed and a design method is proposed. Both the concept and the method are validated by experimental results.

Mutual Synthesis of Combined Microwave Circuits Applied to the Design of a Filter-Antenna Subsystem

A mutual-synthesis approach is presented for the design of subsystems combining two microwave circuits. In this paper, we are focused on subsystems combining a filter and an antenna. In a first step, the methodology consists of synthesizing the global subsystem, which realizes both filtering and radiation functions, with respect to overall specifications. Considering circuits interactions within the subsystem, the resulting constraints are distributed optimally between the two circuits. The latter mutual synthesis then leads, on one hand, to a set of optimal impedances for their connection and, on the other hand, to the corresponding ideal characteristics of each circuit. A solution can then be selected by carrying out a compromise between the simplicity of achieving the characteristics of each circuit and the performances and compactness of the subsystem. In a second step, the circuits are designed independently with respect to the synthesized characteristics. Compared to a classical synthesis approach, where circuits are synthesized independently with respect to a common reference impedance (generally 50 or 75 Omega), the proposed mutual synthesis allows to simplify the global subsystem since interactions between the two circuits are considered and used optimally. The technique is illustrated with the design of a filter-antenna at Ku-band.

Global Design of an EBG Antenna and Meander-Line Polarizer for Circular Polarization

This letter describes a comprehensive approach to design circularly polarized electromagnetic band-gap(EBG) antennas. Some solutions have already been proposed to that end, but they require the design to be started from scratch. With the proposed method, the circular polarization will be obtained through the use of a meander-line polarizer (MLP) located above an existing linearly polarized EBG antenna. Thanks to a global approach, a 20-dBi circularly polarized antenna, boasting an axial ratio (AR) lower than 1 dB over the 29.530 GHz frequency band, has been conceived, realized, and successfully measured.

Frequency Tunable Antenna Using a Magneto-Dielectric Material for DVB-H Application

This paper presents an ultracompact antenna design suited for digital video broadcasting-handheld (DVB-H) reception devices. The DVB-H frequency band is ranging from 4 70 to 862 MHz and divided in 49 channels of 8 MHz. Designed to be integrated in a tablet, it is not only heavily miniaturized (λ0 /49 × λ0/71 ×λ0/160 at 470 MHz), but also able to cover each channel thanks to the use of a magneto-dielectric material. The advantage of using such a material is studied and described in this paper. Moreover, the operating frequency is continuously tuned over the whole DVB-H band by the integration of a varactor diode. This varactor diode has been characterized and modeled to properly cosimulate its behavior within the antenna. Limitations in terms of accepted power by the diode are emphasizing. Finally, the antenna design, including both magneto-dielectric material and varactor diode is integrated in the DVB-H receiver device. Measurement performances are presented and discussed.

3GPP Channel Model Emulation with Analysis of MIMO-LTE Performances in Reverberation Chamber

Emulation methodology of multiple clusters channels for evaluating wireless communication devices over-the-air (OTA) performance is investigated. This methodology has been used along with the implementation of the SIMO LTE standard. It consists of evaluating effective diversity gain (EDG) level of SIMO LTE-OFDM system for different channel models according to the received power by establishing an active link between the transmitter and the receiver. The measurement process is set up in a Reverberation Chamber (RC). The obtained results are compared to the reference case of single input-single output (SISO) in order to evaluate the real improvement attained by the implemented system.

Ultrawideband Dielectric Resonator Antenna for DVB-H and GSM Applications

This letter presents a novel design of compact dielectric resonator antenna (DRA) that is dedicated to ultrawideband applications such as digital video broadcasting-handheld (DVB-H). The dimensions of the radiation element are lambda0/7 times lambda0/13 times lambda0/28 at 466 MHz. A miniaturization technique has been used in order to reduce the antenna size, and a parametric analysis of the antenna is performed. The measured results agree well with the simulated ones. The proposed antenna offers a bandwidth of 70% around 700 MHz for -8 dB impedance matching bandwidth definition and covers the Ultra High Frequency (UHF) IV, V and Global System for Mobile communications (GSM) bands.