Miniature filtering power divider using folded stub-loaded resonator

A miniature microstrip filtering power divider is presented. To effectively reduce the circuit size, the compact folded stub-loaded open-loop resonator is applied to build up the resonator-based power divider with a filtering response. Based on the even-odd-mode analysis, an analytical model of the proposed power divider structure is presented. A prototype of the filtering power divider centered at 3.5 GHz with 3 dB fractional bandwidth of 7.5% is designed, fabricated and measured. The presented power divider has two transmission zeros, which improve the frequency selectivity greatly. The size of the fabricated filtering power divider is 8.4 mm × 13 mm. The measured results are in good agreement with the simulated ones.