Abstract-A new approach to analyze the behavior of a FabryPérot cavity type high-gain antenna covered with a frequency selective surface (FSS) superstrate is presented. Using an image theory and effective constitutive parameter retrieval, properties of impedance and a refractive index of the entire cavity structure are investigated. Through the analysis, we show that our antenna inherently operates in the medium whose maximum magnitude of the refractive index is lower than '0.5'.In consequence, we demonstrate that the high-gain feature of the Fabry-Pérot cavity antenna is not only due to satisfy a conventional cavity resonance condition, but also for a wave collimation effect of a metamaterial with the effectively low index of refraction. To show the collimation effect of the cavity, phase properties of a radiating wave with and without the FSS superstrate are examined. Moreover, the effect of the real and imaginary parts of the refractive index on behaviors of the antenna is also investigated by analyzing the derivative of a realized gain of the antenna within an impedance matched frequency band.

A simulation of the uninsulated duct firestop system was performed to review its application possibility to the building by analyzing the radiant heat transfer and its impact to the surrounding structures in the event of a fire. The simulation targets were divided by the presence or absence of an insulation material (1 m long) as floor and wall duct firestop systems, and the surface temperature, which is an important input data, was based on the existing verification test data. Then, the ambient air temperature, surrounding structure surface temperature, and radiant temperature at some distance from the duct were analyzed through simulations in the modeled virtual spaces. As a result of simulation, it is judged that the application of the uninsulated duct firestop system wrapped by the insulation material can significantly reduce the possibility of fire spreading due to the radiant heat.