Third-Order Filtering Power Divider with Sharp Selectivity

This paper presents a novel microstrip filtering power divider, whose transmission property is featured by a third-order general Chebyshev bandpass response. A transmission zero near the right side of the passband greatly improves frequency selectivity. For demonstration, an example was fabricated and measured, whose center frequency is at 2.5 GHz and 3-dB bandwidth is 16%. The measured results agree well with the simulation ones. Suppression in the stopband is as high as 28 dB over 3th harmonic. In addition, the isolation between two output ports is greater than 17.5 dB over relatively wide frequency range. Compared with other counterparts, the proposed filtering power divider has advantages of sharp selectivity, wideband isolation and good out-of-band performance.