A Simple Approach for Improving Bandwidth and Isolation of Wilkinson Power Divider

Abstract

A simple approach to improve both the bandwidth and isolation of the Wilkinson power divider for using in L-band satellite communications is presented in this paper. To enhance the bandwidth, a multi-section method based on the Chebychev impedance transformation is employed. In order to improve the isolation performance between output ports, the values of isolation resistors are carefully determined by using the iterative approximation method combined with an investigation procedure. In order to validate the proposed design, a two-way and eight-way power divider prototypes were fabricated and tested on a Rogers RO4003C material. Good agreements between simulations and measurements are obtained in a frequency range from 0.8 GHz to 2.2 GHz. The two-way power divider had a fractional bandwidth of 106% with an isolation of better than 30 dB. The eight-way power divider achieved the bandwidth and isolation of 109% and better than 24 dB, respectively. Both the power dividers exhibit the phase imbalance of less than 3 degrees, and amplitude imbalance of less than 0.02 dB. Compared with the other works, the proposed power dividers deliver broader bandwidth and improved isolation while still retaining good insertion loss, low phase and amplitude imbalance in the operation frequency range.