Yoann Letestu

Broadband folded printed quadrifilar helical antenna with wide arms

The printed quadrifilar helical antenna (PQHA) represents a very attractive candidate for many applications such as mobile satellite communications, broadcasting satellite systems or global positioning systems, due to hemispherical radiation, circular polarization, good axial ratio, and low cost. Nevertheless, the bandwidth of a conventional PQHA could be insufficient for such applications. Therefore, in this paper, a technique for increasing the bandwidth of a PQHA by adding a shorted parasitic helix is presented. The new folded printed quadrifilar helical antenna (FPQHA) is designed to achieve 30% of bandwidth in axial-mode. Moreover, due to the printed arms on one substrate face, the FPQHA manufacturing is very simple. Measured results are presented to validate the conceptWith the development of the satellite communication systems (GPS, INMARSAT), the Printed Quadrifilar Helical Antennas (PQHA) have found wide applications due to its features of circular polarization, good axial ratio and its low cost. Nevertheless, they suffer from their narrow bandwidth (5 ∼ 8%), which could be insufficient for such applications.

A size reduced configurations of printed quadrifilar helix antenna

Several methods to reduce the axial length of a printed quadrifilar helix antenna (PQHA) are presented and compared. Using variable pitch angle techniques and different meander techniques, the axial length of the conventional PQHA is reduced by 35% making it practical for implementation on a handheld terminal.

Quadrifilar helical antennas : Wideband and multiband behavior for GPS applications

A novel multi-frequency printed quadrifilar helix antenna based on Multiple arm technique is presented in this paper. Double frequency and satisfactory antenna characteristics are achieved. The antenna has relatively compact size and hemispherical pattern with excellent circularly polarized coverage. The antenna is designed and simulated with the application of HFSS software. The simulation results and analyses are presented.

A mutual coupling correction procedure for antenna arrays

A simple method to evaluate the mutual coupling matrix in an antenna array is presented here. This global mutual coupling correction procedure is independent of the type of antenna. The method is firstly validated for a dipole array and then for a microstrip patch antenna array. Very good agreement between this mutual coupling correction and the reference solution is observed in both cases.