Dual-Wideband Filtering Power Divider Based On Center-Fed Three-Line Coupled Structure

In this article, a dual-wideband filtering power divider is proposed by using a center-fed three-line coupled structure with three open stubs and two isolation resistors. The center-fed three-line coupled structure can generate two wide passbands separated by a transmission zero (TZ). The three open stubs can achieve four TZs around the two passbands, which is conducive to the frequency selectivity. Compared with the reported designs, the bandwidth is extended and the performance of isolation, insertion loss and circuit size can reach balance. The proposed design is implemented with size of 0.22 lambda(g) x 0.39 lambda(g) (lambda(g) is the guided wavelength at the center frequency of the lower passband) which exhibits the 3-dB fractional bandwidths of 56.5%/24.27% and the insertion loss of 0.51/0.68 dB at the center frequency of two passband (f(1)/ f(2)) of 1.94/4.2 GHz, while the isolation at f(1)/f(2) are higher than 22.5/20.1 dB.