Measuring the reflection of electromagnetic waves from foam structures of varied foaming ratio
A specific multi-frequency technique for measuring the reflectivity of constantly collapsing foam structures of varied initial foam ratio is developed. A measuring and computing complex implemented the technique is used. It operates in the microwave range from 38 to 52 GHz. Dynamic foam structures with an initial foaming ratio of 55, 108, and 156 units in the form of flat-layered foam samples with a fixed thickness are under measurement. It is shown that the use of foam structure covering allows to reduce the reflection of electromagnetic waves from metal surfaces significantly. The obtained measurement results confirm the possibility of measuring dynamic foam structures, and this technique makes it possible to separate reflections from the front and back faces of the samples, which is very important for the study of the syneresis processes of the foaming liquid and the destruction of foam structures. The results are useful for studying the radiophysical characteristics of foams and for developers of new foaming agents for various applications where electromagnetic waves are used.