ABSTRACT
Target detection and classification in air defense systems are conditional upon knowledge of electromagnetic parameters of materials of which such targets may be made. Analogously, hiding own objects from being detected requires development of novel materials that will offer enhanced shielding or absorbing properties for incident electromagnetic waves. Traditional methods of such materials' characterization were based on the quasi-free space approach, where material panels would be illuminated by a suitably designed antenna setup, in an environment mimicking their use conditions, i.e., either in an anechoic test chamber or a sufficiently large testing field. Such conditions are not widely available and therefore costly to apply, which hinders the relevant progress in materials' development and testing. The research and development team at QWED develops and promotes an alternative approach to the characterization of shielding and absorbing materials, which is based on resonant (rather than radiating) test-fixtures and conveniently applicable as a desk-top setup in any radio frequency (RF) laboratory. Samples of material-under-test are inserted into an RF resonator, designed by full-wave electromagnetic simulations, and changes in resonant frequencies and Q-factors are noted. By means of the so-called retro-modeling, the relevant material parameters are extracted. This presentation will focus on Single-Post Dielectric Resonators at 5 GHz or 10 GHz, incorporated into static or 2D scanning stages, and providing resistivity, conductivity, or sheet resistance values for representative shielding materials. Other measurement configurations applicable to dielectric, resistive, or conductive materials over a broad microwave-to-millimeter-wave frequency range will also be addressed.
