Design and Modelling of Compact Electromagnetic Sensors for EMC Applications

Abdalghfor Abdalghfar A. ALMTROD

Doctoral thesis

Modelling and simulation in electromagnetic compatibility

Abstract:

This work presents compact electromagnetic sensors usable for electromagnetic compatibility (EMC) measurements. Currently, the utilized standardized 3D antennas are relatively large in size and, in some cases, not very suitable in terms of their electrical parameters and dimensions. This dissertation focuses on the possibility of realizing and using 2D sensors of compact sizes. Five structures of electromagnetic sensors have been designed, fabricated, and tested at the University of West Bohemia's EMC laboratory. Moreover, the practical verifications of the proposed structures showed promising results. The first design is a broadband Printed biconical dipole (PBD) antenna with a balun feeding method. The projection of a classical biconical antenna has inspired the proposed shape. Furthermore, the balun feeding method provides the wide impedance bandwidth. The second structure comprises of 12 elements Printed logperiodic biconical dipole array (PLPBDA) antenna, where each element is derived as the first design. Moreover, PLPBDA antenna exhibited convenient findings in terms of size reduction and bandwidth enhancement. The third design consists of Dual-stacked log periodic biconical dipole array (DSLPBDA) antenna by stacking two LPBDA antennas with angles of 30° and 50° for the inner and outer layers. Regarding the EMC requirements, the achieved radiation pattern results of DSLPBDA antenna enabled it to work as a reference antenna for radiated emission and immunity tests. The fourth work proposes three broadband spiral circular magnetic probes for EMC measurement; One Face Three Loops (1F3L), Two Face Three Loops (2F3L), and One Face One Loop (1F1L) structures. Due to its more selective area, the 1F3L structure performs better than the 2F3L structure while the 1F1L structure offers wider bandwidth than 1F3L one due to reduce the parasitic capacitor. The fifth structure demonstrates a novel highsensitivity magnetic probe switchable from broadband to multinarrowband via a PINdiode. The achieved narrowband high sensitivity is also tuned across the most critical applications with the help of the varactor diode. The frequency and radiation characteristics of the proposed antennas in terms of bandwidth, size, gain, antenna factor and radiation pattern are compared with that of the classical antenna offered for sale. Moreover, the early design of switchable broadband magnetic probe is evaluated alongside the classical magnetic probe offered for sale regarding sensitivity, spatial resolution, and isolation. The comparison results of antennas and probes are listed in tables and showed good agreement.

Abstract:

This work presents compact electromagnetic sensors usable for electromagnetic compatibility (EMC) measurements. Currently, the utilized standardized 3D antennas are relatively large in size and, in some cases, not very suitable in terms of their electrical parameters and dimensions. This dissertation focuses on the possibility of realizing and using 2D sensors of compact sizes. Five structures of electromagnetic sensors have been designed, fabricated, and tested at the University of West Bohemia's EMC laboratory. Moreover, the practical verifications of the proposed structures showed promising results. The first design is a broadband Printed biconical dipole (PBD) antenna with a balun feeding method. The projection of a classical biconical antenna has inspired the proposed shape. Furthermore, the balun feeding method provides the wide impedance bandwidth. The second structure comprises of 12 elements Printed logperiodic biconical dipole array (PLPBDA) antenna, where each element is derived as the first design. Moreover, PLPBDA antenna exhibited convenient findings in terms of size reduction and bandwidth enhancement. The third design consists of Dual-stacked log periodic biconical dipole array (DSLPBDA) antenna by stacking two LPBDA antennas with angles of 30° and 50° for the inner and outer layers. Regarding the EMC requirements, the achieved radiation pattern results of DSLPBDA antenna enabled it to work as a reference antenna for radiated emission and immunity tests. The fourth work proposes three broadband spiral circular magnetic probes for EMC measurement; One Face Three Loops (1F3L), Two Face Three Loops (2F3L), and One Face One Loop (1F1L) structures. Due to its more selective area, the 1F3L structure performs better than the 2F3L structure while the 1F1L structure offers wider bandwidth than 1F3L one due to reduce the parasitic capacitor. The fifth structure demonstrates a novel highsensitivity magnetic probe switchable from broadband to multinarrowband via a PINdiode. The achieved narrowband high sensitivity is also tuned across the most critical applications with the help of the varactor diode. The frequency and radiation characteristics of the proposed antennas in terms of bandwidth, size, gain, antenna factor and radiation pattern are compared with that of the classical antenna offered for sale. Moreover, the early design of switchable broadband magnetic probe is evaluated alongside the classical magnetic probe offered for sale regarding sensitivity, spatial resolution, and isolation. The comparison results of antennas and probes are listed in tables and showed good agreement.

Keywords

Electromagnetic sensor, Electromagnetic interference, Electromagnetic compatibility, PBD antenna, PLPBDA antenna DSLPBDA antenna, and Magnetic probe.

Language used: English

Date on which the thesis was submitted / produced: 19. 10. 2023

Accessible from:: 31. 12. 2999

Thesis defence

• Supervisor: Ing. Zdeněk Kubík, Ph.D.

University of West Bohemia

Faculty of Electrical Engineering

Doctoral programme / field:
Electrical Engineering and Information Technology / Electrical Engineering and Information Technology