Elevated and tapered microstrip coupled ENZ SIW sensor for microwave testing of radome and building materials in 3G and ISM bands

In this paper, an attractive multi-tunnel epsilon near zero (ENZ) substrate integrated waveguide cavity sensor (SIWCS) coupled with the elevated and tapered microstrip line is proposed. The unique combination of the elevated and tapered microstrip excitation provides fair coupling to the proposed dual-band ENZ SIW sensor, eliminates the finite ground plane effect by eradicating the higher order modes of microstrip and allow the integration of the proposed sensor with the monolithic microwave integrated circuit (MMIC) and components. The novel two tunnel SIW ENZ structure is designed and modeled using the computer simulation technology (CST) to work in the dual band of frequency i.e. 1.9 GHz of GSM 3G band and 2.45 GHz of ISM band. The sensitivity analysis of the proposed sensor is performed in a wide range of the dielectric constant of material under test (MUT). The numerical analysis is performed to check the accuracy of the proposed technique to characterize the dielectric materials at both the tunneling frequency. A number of the radome, planar substrate, and building materials are tested using the numerical model of the proposed novel ENZ SIW sensor. The results are typically found to be more than 95% accurate when compared with the original data, which validates the applicability of the proposed technique.