Patrice Brachat

Dual-polarization slot-coupled printed antennas fed by stripline

This article presents recent techniques in the field of dual-polarization printed antennas for designing shielded radiating structures with high-quality performances in terms of cross-polarization level and input-port isolation. The use of gridded patches provides a natural solution to filtering surface currents and is of key importance in limiting inter-element coupling in arrays. Experimental results obtained on various designs are presented. >

Rigorous analysis of three-dimensional structures incorporating dielectrics

The paper presents the SR3D software (3D radiating structures), which calculates the electromagnetic characteristics of arbitrarily shaped structures incorporating dielectric material. The rigorous analysis method is based on the integral equation formulation. The authors included a variational approach using the reaction concept of Rumsey. The problem is numerically solved with a surface finite elements method. A guided mode excitation has been introduced in order to compute the reflection coefficient at the transmit port and the transmission coefficient between the different parts fed by guided modes. This software is validated by excellent agreement between simulated and measured radioelectric performances (patterns and SWR). >

Neutralized Coupling Elements for MIMO Operation in 4G Mobile Terminals

A novel multiple-input-multiple-output (MIMO) dual-antenna system covering the low LTE700 and GSM850/900 communication standards is proposed for mobile terminals. The two-port antenna system is composed of two 3-D coupling elements, placed on the vertices of the short corner of a rectangular FR4 substrate. This rectangular shape emulates the printed circuit board of a modern mobile terminal. To achieve high port-to-port isolation, the neutralization technique is applied. Simulated reflection coefficients, total efficiencies, and envelope coefficient correlation are compared to measured data showing good agreement and competitive performance.

HDI organic technology integrating built-in antennas dedicated to 60 GHz SiP solution

During past years, various research teams have been implied in the development of 60 GHz chipset solutions, using both BiCMOS and advanced CMOS technologies. But for the 60 GHz market to flourish not only low cost RFICs are required, low cost antennas and packages are also key points. So far, HTCC technology has been seen as the chosen one when targeting millimeter wave (MMW) applications. But since 60 GHz applications are targeting large volume consumer applications, the pressure on the cost of the packaging will become higher and it is highly desirable to explore alternative lower cost solutions than HTCC. In this paper, we present 60GHz integrated antennas in an innovative low cost High Density Interconnect (HDI) organic technology demonstrating promising high-gain antenna solution (>; 7 dBi).

Measurement setup and associated calibration methodology for 3D radiation pattern of probe-fed millimeter-wave antennas

In this paper, we present a radiation pattern measurement setup for probe-fed millimeter-wave antennas and the associated calibration procedure. Compared to other existing facilities, our setup has one major innovation: it is composed of two rotating arms allowing measuring the radiated field of a probe-fed antenna over the quasi-3D sphere. The calibration challenges and issues encountered at 60 GHz are thoroughly described. We especially detail a dedicated calibration procedure to improve the accuracy of the measurements. To illustrate our methodology, the 3D radiation pattern measurement of a monopole-type antenna etched over a glass substrate is presented. Experimental results are compared versus simulation results.

Efficiency Measurement of Probe-Fed Antennas Operating at Millimeter-Wave Frequencies

In this letter, we propose a new method to compute the radiation and total efficiency of millimeter-wave probe-fed antennas. This hybrid method combines the measurement of the realized gain radiation pattern over a quasi-3-D sphere and the simulation values of this realized gain over the nonmeasured part of this sphere. To demonstrate the usefulness of the method, 60-GHz probe-fed antennas radiating in broadside, backside, and endfire directions with high, medium, and low directivity are measured. To validate the accuracy of the method, the computed efficiencies of those antennas are compared to simulation results.

An adaptive beam steering antenna for mobile communications

The development of communication systems intended to satisfy the needs for mobility leads to the use of increasingly complex base stations. The studies presented here are related to the design of a reconfigurable material which will steer the radiation in the angular sectors desired to distribute the services of communications. This new type of base station antenna associates an omni-directional antenna to a cylindrical controllable metallic electromagnetic band gap (EBG) material. The main characteristic of this lattice is to include PIN diodes along the metallic wires in order to control the conductivity of each wire and so the angular sectors where transparency of the cylindrical EBG is needed. After a presentation of the controllable EBG material and the beam steering principle, we present the antenna with the reconfigurable reflector including 1080 diodes and we show the EM performances of this kind of structure

Inkjet Coplanar Square Monopole on Flexible Substrate for 60-GHz Applications

In this letter, the design, fabrication, and measurement of a 60-GHz printed antenna with inkjet technology over a flexible substrate is presented. The antenna is a coplanar square monopole with omnidirectional radiation characteristics. We especially measured a 68% total efficiency and a maximum realized gain of 1.8 dBi. This study demonstrates the inkjet technology being a competitive solution for efficient radiating elements at millimeter-wave frequencies.

Industrial HTCC Antenna-Module SiP for 60-GHz Applications

During recent years, various research teams have developed 60-GHz chipset solutions, using both BiCMOS and advanced CMOS technologies. However, for the 60-GHz market to flourish, not only low-cost RFICs are required, but also cheap antennas and package solutions. In order to address these two last issues, we present the design of a Tx-Rx antenna-module using industrial high-temperature co-fired ceramics (HTCC) substrate for millimeter-wave (MMW) large-volume consumer applications. The antennas are integrated within the module. Measured realized peak gain is above 6 dBi over the 57-66-GHz frequency band.

A Dual Frequency Ka-Band Printed Fresnel Reflector for Ground Terminal Applications

Satellite-based telecommunication systems operating in Ka-band require high gain ground terminal antennas. A promising architecture based on dual frequency printed Fresnel reflectors is presented in this paper. The complete development of this antenna including its design methodology, manufacturing, and testing is described. In order to scan its beam, the proposed antenna system can either be combined with electric motors or be transformed into a reconfigurable reflectarray system by replacing the passive reflecting cells by reconfigurable ones. A possible way of implementing such electronically reconfigurable reflecting cells is also presented.