Simple miniaturized Wilkinson power divider using a compact stub structure

Abstract

The paper presents a study on the miniaturization of microwave power dividers/ combiners. The authors propose a modified two-way Wilkinson power divider with dimensions of 33×24mm, twice reduced compared to the standard structure (65×24mm). This new structure has been designed based on an "artificial transmission line" consisting of a microstrip line and two shunt capacitors at its edges where the capacitors are replaced by two open-ended stubs located inside the circuit loop and do not take any additional space. The power divider has good performance at the designed frequency 900 MHz and its bandwidth of over 1 GHz is sufficient for various applications. The simulation has been performed in both Agilent ADS/ Momentum and CST Microwave Studio and good agreement of the results obtained in these design tools was obtained. Two prototypes have been fabricated and tested, and the measurement results fit well with the simulation. This approach can be applied to design other microwave circuits where quarter-wavelength transmission lines are required, and the modified Wilkinson power divider can be used for various applications such as measurement systems or in antenna array feeding circuits.