Microwave permittivity of MWCNT, Ca_{1 − x}Ba_xBi₂Nb₂O₉ (0 ≤ x ≤ 1) and MWCNT/ Ca_{1 − x}Ba_xBi₂Nb₂O₉ (0 ≤ x ≤ 1) layered composite thick films using microstrip ring resonator overlay method

The microwave dielectric properties of the multiwalled carbon nanotubes (MWCNT) thick film, Ca_{1 − x}Ba_xBi₂Nb₂O₉ (x = 0, 0.2, 0.4, 0.6, 0.8, and 1) (CBBNO) thick films, and MWCNT/CBBNO layered thick film composites in the 8–18 GHz were determined by the overlay method using the microstrip ring resonator (MSRR). Microwave properties were studied by perturbation of MSRR due to the overlay of thick films of different materials. The MWCNT thick film, CBBNO thick film, and MWCNT/CBBNO layered composite thick films were screen-printed on an alumina substrate. The experimental data was obtained for the material and/or composition dependent peak output and the resonance frequency of the MSRR. In addition, the numerical results were obtained for first harmonic radiated in the X-band region from the MSRR operating in Ku-band (15.45 GHz) frequency region. The comparison was done for the X and Ku-band responses of MSRR due to perturbation of screen-printed MWCNT thick film, CBBNO thick film, and MWCNT/CBBNO layered thick film composites.