A Continuously Tunable Wilkinson Power Divider with a Flat Division Ratio

In this paper, a Wilkinson power divider with flat and continuously tunable division ratio is presented. A pair of adjustable networks are utilized to achieve a flat division ratio and good matching performance within a specific frequency range. Each network consists of two varactor diodes and three segments of transmission lines, which is equivalent to a quarter-wavelength transmission line with tunable characteristic impedance. By adjusting the capacitance of the varactor diodes, the equivalent electrical length of the network can be maintained at 90 degrees while its equivalent characteristic impedance is varied. For verification, a proposed power divider with a continuously tunable range of 3.2-5.8dB is designed and fabricated.