In this paper, a sensor using modified Split Ring Resonators (SRRs) is designed, simulated, fabricated, and used for advanced investigation and precise measurements of the real part and imaginary part solid dielectrics’ permittivity. Adding vertical strips tightly coupled to the outer ring of the SRR leads to the appearance of two resonant frequencies at 1.24 GHz and 2.08 GHz. This modified geometry also assures an improved sensitivity. Using the full wave electromagnetic solver, both the unloaded and loaded sensors are investigated. The numerical simulations are used to develop a mathematical model based on a curve fitting tool for both resonant frequencies, allowing to obtain analytical relations for real and imaginary parts of permittivity as a function of the sample’s thickness and quality factor. The sensor is designed and fabricated on 1.6 mm thick FR-4 substrate. The measurements of different samples, such as transparent glass, acrylic glass, plexiglass, and Teflon, confirm that the modified SRR sensor is easy to implement and gives accurate results for all cases, with measurement errors smaller than 4.5%. In addition, the measurements highlight the importance of the second resonant frequency in the cases in which numerical limitations do not allow the usage of the first resonant frequency (1 mm thick sample).

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The need for low cost gas sensors has been required especially for home usage. Possible applications are, in buildings or basements where possible toxic gases can be accumulated, for example carbon monoxide, carbon dioxide, methane. This paper presents a first step in developing gas sensors based on impedance measurements. For optimal sensor operation a heater that should ensure uniform heating of the structure is required. We have proposed and realized a series of three geometries with different materials that will serve as heaters for future sensor development. The element of novelty consists in the use of flexible substrates. The heater will be supplied with appropriate voltage in order to obtain a working temperature between 80 and 100 °C. The temperature distribution was firstly simulated and subsequently measured by thermographical methods

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