Narrow-band power dividers with wide range tunable power-dividing ratio

This paper presents two narrow-band power dividers with a wide range power-dividing ratio based on the two new controlling insertion loss methods, which are low-impedance line and coupling capacitor. Initially, a narrow-band BPF is designed based on the equivalent circuit model and LC equivalent circuit. Then, using the surface current density, it is determined by which part of BPF structure the insertion loss (IL) can be controlled at center frequency. The tunable Wilkinson power dividers (TWPDs) are designed based on IL control components to create a wide range of power-dividing ratios, using only two DC voltages. The center frequency of first designed TWPD is 2.5 GHz, and the power-dividing ratio can be controlled up to 1:45 by variation of two DC voltages from 0 to 8 V. Since the structure of TWPDs are symmetric, the inverse voltages results in the inverted divided power between the output ports. The center frequency of second designed TWPD is 2.52 GHz, and power-dividing ratio can be controlled up to 1:134 by variation of two DC voltages from 1.7 to 4 V. Two proposed TWPDs are fabricated and measured. Comparisons of the measured and simulated results are presented to verify the theoretical predictions.