Cascaded splitter/combiner microstrip sections loaded with complementary split ring resonators (CSRRs): Modeling, analysis and applications

摘要

This paper is focused on the study of splitter/combiner microstrip sections where each branch is loaded with a complementary split ring resonator (CSRR). If the structure is symmetric with regard to the axial plane, only one transmission zero (notch) in the transmission coefficient arises. Conversely, two notches appear if symmetry is disrupted. A model that combines lumped elements (describing the CSRR-loaded line sections) and distributed components (accounting for the transmission lines) is proposed and used to obtain the position of the transmission zeros. The model is validated through parameter extraction and comparison to electromagnetic simulations and measurements, where up to three cascaded splitter/combiner sections (symmetric and asymmetric) are considered. Finally, the three-section symmetric structure is asymmetrically loaded to demonstrate the possibility of using the proposed device as a microwave sensor/detector able to identify defects or abnormalities between a sample under test (SUT) and a reference sample. With this technique, as many samples as splitter/combiner sections can be sensed simultaneously.