Diseño analítico de filtros multibanda con líneas de transmisión multiconductoras y stubs en abierto

Abstract

A new topology for implementing multiband bandpass filters is presented in this paper. Two identical shortcircuited multiconductor transmission lines (MTL) and several shunt open stubs are interconnected to achieve the desired frequency response. Using this configuration, zeros are forced in the passband of the MTL, creating a multiband bandpass filter. As both, the MTLs and the stubs are distributed elements, spur-line band-stop filters are added in order to mitigate the first replicas of the structure. To assess the developed theory, a prototype consisting of a 4 fingers-MTL and two shunt open stubs is simulated, showing a good agreement between analytical and simulated results. Furthermore, it is possible to establish a design criterion that allows to synthesize multiband responses, varying just some parameters of the MTLs and the stubs.