An accurate analytic solution for the radiated fields from resonant multifilar helix antennas

The analysis of a resonant multifilar helical antenna composed of Q helices, where Q is an arbitrary even number, is investigated. A simple method is applied to get accurate analytic formulae for the far fields radiated from such an antenna. Each helix of the antenna has arbitrary number of turns with a length of integer multiples of λ/4. The moment method employing a Galerkin´s technique is also applied to get the radiation fields for the sake of examining the accuracy of the analytic formulae. Unlike the numerical techniques, which are time and memory consuming when used for wire antenna design, these analytic formulae provide a simple and fast tool for the multifilar helix antenna design. The radiation pattern, polarization, and input impedance of multifilar helix antennas are presented and compared with the results that obtained using the method of moments showing good agreement.