SIW-based microfluidically tunable PD with wide-frequency-tuning range

A passive microfluidically tunable power divider (PD) with a wide-frequency-agile range based on substrate integrated waveguide (SIW) has been presented. The proposed structure consists of two SIW resonators loaded on the same complementary split-ring resonator and five identical filling-water tubes placed on the top plane. By injecting water into five tubes, the effective permittivity of the substrate can be controlled, and thus the operating frequency of the PD can be precisely tuned. For demonstration, the proposed PD is designed and fabricated. The measured and simulated results are given, showing good agreement.