The increased use of carbon-fiber composites in unmanned aerial vehicles is a challenge for their EMC assessment by numerical solvers. For accurate and reliable simulations, numerical procedures should be tested not only for individual components, but also within the framework of complete systems. With this aim, this paper presents a benchmark test case based on experimental measurements coming from direct-current injection tests in the SIVA unmanned air vehicle, reproduced by a numerical finite-difference-time-domain solver that employs a new subgridding scheme to treat lossy composite thin panels. Validation was undertaken by applying the feature selective validation method, which quantifies the agreement between experimental and numerical data.

Radar high resolution range profiles are widely used among the target recognition community for the detection and identification of flying targets. In this paper, singular value decomposition is applied to extract the relevant information and to model each aircraft as a subspace. The identification algorithm is based on angle between subspaces and takes place in a transformed domain. In order to have a wide database of radar signatures and evaluate the performance, simulated range profiles are used as the recognition database while the test samples comprise data of actual range profiles collected in a measurement campaign. Thanks to the modeling of aircraft as subspaces only the valuable information of each target is used in the recognition process. Thus, one of the main advantages of using singular value decomposition, is that it helps to overcome the notable dissimilarities found in the shape and signal-to-noise ratio between actual and simulated profiles due to their difference in nature. Despite these differences, the recognition rates obtained with the algorithm are quite promising.

A new indoor facility for electromagnetic measurements has been developed and built at the Detectability and Electronic Warfare Laboratory, INTA, Spain. The system was designed to extend the previous capabilities so that not only monostatic but also bistatic radar cross section (RCS) tests could be easily conducted. Due to limited space, far-field radar cross sections in the system are restricted to small targets, but this layout will allow the researchers to investigate ReS near-field-to-far-field transformations. The system was also conceived to be versatile enough to carry out other tests, such as near-field antenna measurements, material-absorption measurements, and electromagnetic characterization of materials. The paper describes the novel concept behind the facility, and presents some preliminary measurement results on different applications.

Open area test sites (OATS) have been traditionally employed for aircraft electromagnetic compatibility certification tests because of the large size of these items. In this regard, unmanned aerial vehicles (UAVs) have emerged in the last years and, albeit being sometimes notably smaller, yet they have to accomplish for the same certification process. This paper investigates into the possibility of using a reverberation chamber for performing two aircraft low-level coupling tests, namely, low-level direct drive and low-level swept fields, and compares the results with those obtained in an OATS, in both cases using a representative part of a UAV.

The trend in the last few decades is that current unmanned aerial vehicles are completely made of composite materials rather than metallic, such as carbon-fiber or fiberglass composites. From the electromagnetic point of view, this fact forces engineers and scientists to assess how these materials may affect their radar response or their electronics in terms of electromagnetic compatibility. In order to evaluate this, electromagnetic characterization of different composite materials has become a need. Several techniques exist to perform this characterization, all of them based on the utilization of different sensors for measuring different parameters. In this paper, an implementation of the metal-backed free-space technique, based on the employment of antenna probes, is utilized for the characterization of composite materials that belong to an actual drone. Their extracted properties are compared with those given by a commercial solution, an open-ended coaxial probe (OECP). The discrepancies found between both techniques along with a further evaluation of the methodologies, including measurements with a split-cavity resonator, conclude that the implemented free-space technique provides more reliable results for this kind of composites than the OECP technique.