Linear Fabry-Perot/Leaky-Wave Antennas Excited by Multiple Sources

Fabry-Perot (FP)/leaky-wave antennas fed with multiple sources are analyzed and modeled. A transmission line (TL) approach for a rapid and efficient analysis of such antenna configuration is developed. The method is based on the superposition of the traveling leaky waves excited by each of the applied sources. The field distribution inside the cavity is derived by using a longitudinal TL model which takes into account the interference of the multiple leaky waves excited by the sources. The radiation pattern of the multiple fed antennas is obtained by using the fast Fourier transformation of the field distribution. The propagation constants of the leaky waves, traveling inside the FP cavity, are computed analytically, and the accuracy of the proposed expressions is verified by using the transverse resonance method approach. A novel and accurate closed-form expression for the leaky-wave propagation constant has been derived. A detailed analysis of the antenna properties is carried out by using the model showing how this antenna configuration is suitable for designing very large aperture antennas with very high gain and fairly acceptable bandwidth. A prototype of a multifeed FP antenna has been fabricated by using 3-D printing technology and tested.