A Synthesis Method for <italic>N</italic>-Section Unequal Ultra-Wideband Wilkinson Power Divider With Controllable Equal-Ripple Performance

Abstract

In this paper, a novel synthesis method is presented to design of a class of multi-section ultra-wideband (UWB) Wilkinson power dividers (WPDs) with an arbitrary power ratio. The proposed UWB-WPD topology consists of $N$ cascaded asymmetric coupled line sections (ACLSs) and $N$ isolation resistors. Through even- and odd-mode analysis, the proposed synthesis method is demonstrated with a few unique novelties as summarized: (1) It is for the first time proved that the first kind Chebyshev equal-ripple performance can be exactly realized by the cascaded transmission-line transformer without Hansen’s approximation; (2) It is also for the first time revealed that all the $S$ -parameters ( $S_{11}$ , $S_{21}$ , $S_{31}$ , $S_{22}$ , $S_{33}$ and $S_{32}$ ) of proposed WPD can achieve controllable in-band equal-ripple performance. To verify the effectiveness of proposed synthesis method, several design examples are presented and designed for demonstration of varied equal-ripple responses. Finally, two WPD circuits with $N = 3$ are fabricated, and the measured results well validate the predicted ones from proposed method.

Keywords

• Asymmetric coupled line section (ACLS)
• first-kind Chebyshev frequency response
• ultra-wideband (UWB)
• Wilkinson power divider (WPD)