Control of rejection frequency and density of output spectrum by programming nonuniform two channels with ternary fluidic system

Abstract

The growth of multi-functional wireless systems has made selecting the operation frequency and rejecting unwanted frequencies very difficult because of the interferences in dense spectra. Compared to conventional electronic tuning devices, microfluidic channels have great potential because of the greater design freedom and fewer parasitic effects. Previously, single or uniform microfluidic channels have been used for microwave sensors, antennas, or filters. In this study, a rejection frequency control filter was constructed by programming two nonuniform channels with a ternary fluidic system. To obtain two nonuniform channels with a wide tuning range, a novel defected ground cavity structure was designed. When three different fluids are used as '0', '1', and '2' inputs for the ternary fluidic system, it outputs nine different rejection frequencies. The density of the output spectrum can be controlled by designing either uniform or nonuniform channels in the proposed fluidic system. For instance, uniform channels produce sparse frequency channels between 1.95 and 3.55 GHz. By contrast, the nonuniform channels produce dense and successive frequency spectra ranging from 2.5 to 3.32 GHz. Thus, the tuning range of uninform channels is wider than that of nonuniform channels.