A Field Performance Evaluation Scheme for Microwave-Absorbing Material Coatings

Abstract

Performance evaluation is an important aspect in the study of microwave-absorbing material coatings. The reflectivity of the incident wave is usually taken as the performance indicator. There have been various methods to directly or indirectly measure the reflectivity, but existing methods are mostly cumbersome and require a strict testing environment. What is more, they cannot be applied to field measurement. In this paper, we propose a scheme to achieve field performance evaluation of microwave-absorbing materials, which adopts a small H-plane sectoral horn antenna as the testing probe and a small microwave reflectometer as the indicator. When the size of the H-plane sectoral horn antenna is specially designed, the field distribution at the antenna aperture can be approximated as a plane wave similar to the far field of the microwave emitted by a radar unit. Therefore, the reflectivity can be obtained by a near-field measurement. We conducted experiments on a kind of ferrite-based microwave-absorbing material at X band (8.2-12.4 GHz) to validate the scheme. The experimental results show that the reflectivity is in agreement with the reference data measured by the conventional method as a whole.

Improved technique for radar absorbing coatings characterization with rectangular waveguide and numerical modeling

“…This can be done by employing measurement technique suitable to extract these parameters using a probe, which provides the necessary conditions of such applications of measurements. Currently, radar absorbing coatings are characterized by directly measuring the reflection coefficient using horn antenna from reflected wave of a plane wave incident normally on coatings at a given frequency point [10]. The drawback of this method is that the horn antenna should be carefully designed in order to obtain approximated plane wave at the aperture of the antenna.…”