Performance and non-destructive evaluation methods of airborne radome and stealth structures

In the past few years, great effort has been devoted to the fabrication of highly efficient, broadband radome and stealth (R and S) structures for distinct control, guidance, surveillance and communication applications for airborne platforms. The evaluation of non-planar aircraft R and S structures in terms of their electromagnetic performance and structural damage is still a very challenging task. In this article, distinct measurement techniques are discussed for the electromagnetic performance and non-destructive evaluation (NDE) of R and S structures. This paper deals with an overview of the transmission line method and free space measurement based microwave measurement techniques for the electromagnetic performance evaluation of R and S structures. In addition, various conventional as well as advanced methods, such as millimetre and terahertz wave based imaging techniques with great potential for NDE of load bearing R and S structures, are also discussed in detail. A glimpse of in situ NDE techniques with corresponding experimental setup for R and S structures is also presented. The basic concepts, measurement ranges and their instrumentation, measurement method of different R and S structures and some miscellaneous topics are discussed in detail. Some of the challenges and issues pertaining to the measurement of curved R and S structures are also presented. This study also lists various mathematical models and analytical techniques for the electromagnetic performance evaluation and NDE of R and S structures. The research directions described in this study may be of interest to the scientific community in the aerospace sectors. (topical review)