A novel compact tunable coupled-line power divider using varactors

In this paper, a novel compact tunable coupled-line power divider using varactors is presented. It has a compact circuit due to the coupled line with short electrical length. The operating frequency can be flexibly controlled by the bias voltage because the capacitance of the varactors is regulated by the applied bias voltage. The theory of this power divider is analyzed and a microstrip example of this tunable power divider is designed, fabricated, and measured. The measured results indicate that the operating frequency of the proposed tunable power divider ranges from 0.8 to 1.15 GHz, agreeing well with the simulated result.