Ammonia adsorption-induced change in permittivity of zeolite Y in millimeter-wave band

Abstract

Millimeter wave is a prominent topic for next-generation communication system. To develop functional materials to be used in sensors operated in the millimeter-wave, it is necessary to obtain the variation in the permittivity of the materials. In this study, the effect of ammonia adsorption on the permittivity of zeolite Y in the millimeter-wave of 60–90 GHz is investigated. The results indicate that the ammonia adsorption increases the permittivity of zeolite Y. Specifically, the permittivity change of the gas concentration resulted in 0.025/100 ppm. Based on the characterizations and calculation, ammonia adsorption in zeolite Y stretches the bond between mobile cations and zeolite framework, which results in an increase in the ionic dipole moment of the zeolite. This study provides a fundamental insight on gas sensing materials for millimeter-wave sensors.