Marc Thévenot

Synthesis of Antenna Arrays and Parasitic Antenna Arrays with Mutual Couplings

A synthesis method to design multielement antennas with couplings is presented. The main objective is to perform a rigorous determination of the electromagnetic characteristics involved in the design, especially with arrays of moderate sizes. The aim is to conceive jointly and efficiently the antenna and the circuits to connect (feed distribution network, power amplifiers, reactive loads, etc.). The subsequent objective is to improve the understanding and capabilities of strongly coupled antennas. As a whole, the synthesis procedure is then applied to different antenna architectures in order to show its efficiency and versatility. A focus on some antenna concepts where the management of couplings is a key factor to improve the performances is presented. After describing the synthesis procedure, the first category of coupled multielement antenna studied concerns radiating arrays in linear or circular polarization. A design including couplings effects on an active array is also presented. Then, the method is applied to parasitic antenna arrays and a specific investigation on reflectarray antenna is performed as they can be considered as a particular case of parasitic arrays.

Electromagnetic nonlinear modeling of active phased antenna

This paper examines the distinctive feature of studying the direct interaction between high power amplifiers located at the vicinity of the radiating elements without the use of isolators. In that case, the coupling effect between antennas, which leads to output impedance mismatching and degradation of the radiation pattern, will be described. Alongside, two methods have been developed to address this major drawback with some experimental results to validate the theoretical approach. An active antenna prototype including power amplifiers has been manufactured to validate a first approach of active antenna joint simulation, taking into account all the mentioned effects.