Filtering Leaky-Wave Antenna With Series-Coupled Patch Array

Abstract

A design of leaky-wave antenna with series-coupled patch array based on integrated filtering function is proposed. Methods of filter synthesis are utilized to analyze its filtering networks. An equivalent filter circuit with lossy coupling model between patches is derived for characterizing the coupled patch array with a finite length. The relationship between the equivalent circuit and the structure parameters is revealed for the optimization design of the filtering antenna. Impedance matching at ports is considered in optimization due to the lossy coupling and the feeding structure. The method's validity is demonstrated by theoretical derivation, simulation, and measurement. The measured results show the radiation angle and peak gain of the fifth-ordered filtering antenna from 12 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$^{\circ }$</tex-math></inline-formula> to 43 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$^{\circ }$</tex-math></inline-formula> and 9.23 to 10.36 dBi, respectively, as the frequency varies from 2.4 to 2.6 GHz.