A UWB 1 to 4 wilkinson power divider with triple high-Q band-notched characteristic using U-shaped DGS

Reducing the interference between ultra wideband (UWB) and existing wireless communication systems has become of importance recently. In this study, we propose an equal 1 to 4 power divider (PD) which enables the suppression of three different frequencies, 3.95, 5.2 and 5.8 GHz, in the UWB frequency band by means of U-shaped defected ground structure (DGS). In this respect, it is essential to provide steep band-rejection with high Q-factor. The authors have used a novel method to attain this goal using U-shaped DGS. Studies show that there is a relation between the line width and Q-factor of a given band-notched structure. Therefore, instead of using a 50-50-50 ohm configuration, a 50-100-50 ohm transformation is used which has a narrower line width in the middle of the PD providing a steeper suppression with a high Q-factor. The measured Q-factor compared to similar structures is higher having a value of 27.5 with more than 30 dB suppression.