Linear Tapers: Analysis, Design and Applications

Abstract

Linear tapers are the most common taper which are used for impedance matching networks and also in the design of filters, power dividers, antennas, etc. Surprisingly, they have not been theoretically characterized in the literature. By using theory of small reflections, the characteristics of linear impedance taper (generalized case) and linear width taper (approximate case) have been analyzed in terms of reflection coefficient and results are compared with characteristics of other tapers which validated the same. It has been found that reflection coefficient response for the linear tapers is very close to exponential taper. Moreover, using linear width taper, a novel linearly tapered coupled-line ultra-broadband bandpass filter is designed which possesses a very compact size of $0.34{\lambda _{{g_0}}} \times 0.26{\lambda _{{g_0}}}$ and wide 10 dB passband of 4.5 to 12 GHz.