978-1-5386-5728-7/18/$31.00 ©2018 IEEE Characterization of Time Domain EM Field Double-loaded Curved Loop Probe Marc Pous, Marcos Quílez, Mireya Fernández and Ferran Silva Grup de Compatibilitat Electromagnètica Universitat Politècnica de Catalunya Barcelona, Spain email: marc.pous@upc.edu Abstract— in this paper, we present and analyze the performance of a double-loaded curved loop probe to measure simultaneously electric and magnetic fields (EMF). The aim is to construct a probe that can be fitted to non-planar structures and have a proper response to EMF. The curved probe is studied in comparison with well-known planar probes, which have been verified and used previously. The time-domain data obtained through EM simulation allow us to identify if the probe’s response is suitable although its geometry. Finally, the probe has been constructed and evaluated with experimental test, measuring and validating the conclusions find out by the EM simulation. Keywords— Time-domain measurements, Electromagnetic interferences, double-loaded loop probe, FDTD, EM simulation I. INTRODUCTION In the field of Electromagnetic Compatibility (EMC), Electromagnetic Field (EMF) probes are necessary to measure interference. Industries like the aeronautics, healthcare, railway or automotive need these probes to quantify the incident EMF at their equipment [1],[2],[3]. However, the placement of EMF probes usually produces distortion of the fields and other times it is not possible to allocate them. Moreover, the EMF probes available at the market are broadband probes, which integrate the response of the full bandwidth in a single value. Hence, there is no way to decompose the measured signal at the frequency domain, being not possible to measure separately a single or various frequency bands, which is necessary to evaluate interference to the communication systems. To overcome this limitation and accomplish with the objective, time-domain based probes are developed. In previous publications [4], laser probes are directly connected to oscilloscopes in order to obtain the EMF. Making possible to find out the electric field (E-Field) and the magnetic field (H-Field) at the same time that the time-domain data is stored. Therefore, these broadband EMF probes in combination with post-processing allow us to split interferences and analyze separately any desired frequency band. In this paper, these time-domain based probes will be used and modified with the idea of attaching them to structures. Currently, the possibility that novel materials and technologies like the 3D printing offers us novel approaches to construct EMF probes fitting the shape with a non- invasive probe. As an example, the aeronautic industry is interested in developed probes that can be fitted to composite fuselage structures instead of placing them in the middle of the bay. For this reason, we will study if it is suitable to curve the probe and still have a device, which is capable of measuring simultaneously the electric and the magnetic field in a traceable and confident way. Even more, with this approach of constructing sensors within the structure, we can dismiss the magnitude of the E-Field or the H-Field and focus on the voltages and currents coupled at a certain structure when we are interested in comparative results. The same approach is done in EM simulation when currents and voltages are computed at cables, or other equipment parts. Therefore, we are developing a curved double-loaded loop probe to compute the E-Field and the H-Field, characterizing its performance through EM simulation and experimental measurements. In section II, the double-loaded curved loop is described. In section III, EM simulation is employed to view if an excessive curvature of the loop produces an undesired performance of the probe, measuring high field components where no probes’ response Is expected. Finally, in section IV, the curved probe presented in section II is evaluated within EUROTEM®2 cell to corroborate the conclusions obtained at the simulation stage. II. DOUBLE-LOADED CURVED LOOP PROBE A. Planar double-loaded loop probe The reference EMF double-loaded loop probe has a planar shape validated in previous works [4]. In fact, E-Field was measured with this probe within the cavity of an Unmanned Aerial Vehicle (UAV) fuselage, comparing its successful results with other commercial probes (Fig. 1). Fig. 1. Planar double-loop probe employed to measure the EMF within the fuselage of an unmanned air vehicle. A double-loaded loop probe is a loop with two gaps at opposite sides loaded with identical loads. The probe was presented by King in 1969 [9] and later developments of Kanda and Wieckowski in 1980s [10], [11]. The presence of an electromagnetic field induces a current within the loop, which is the contribution of the E-Field and the H-Field. Meaning that the response of the probe is equivalent to the superposition of an electric dipole and a magnetic loop. The addition of the signal is directly related with H-Field and the Authorized licensed use limited to: UNIVERSITAT POLITECNICA DE CATALUNYA. Downloaded on April 05,2022 at 09:35:14 UTC from IEEE Xplore. Restrictions apply.