Long-range RFID emitter antennas for passive keyless entry systems: Page 4 of 4

October 10, 2016 //By Jorge Rodriguez
Passive keyless entry (PKE) is among the recent technologies introduced into the automotive sector one of the trendiest. No doubt! Touching the door handle or approaching to it and automatically opening is like dark magic.

Our first approach presented in the International Trade Fair for Electronics Components, Systems and Applications in Munich 2014 is currently in advanced state with great expectations, settled in a consortium with top research institutions such as Centro de Electrónica Industrial (CEI-UPM), Instituto de Ciencia de Materiales de Madrid (ICMM-CSIC), and  Grupo de Síntesis y Procesado de Materiales (SIPMAT-UC3M) is under a research and development project granted by Centro para el Desarrollo Tecnológico Industrial (CDTI).

Polymer bonded magnetic (PBM) blend is envisioned as a solution to withstand drop test and lower the weight. The elastic bonding between particles and polymeric matrix provide an ideal damping behavior and simultaneously weight reduction from lowering particles content up to 70% and limiting protective plastic case material. Soft magnetic micro-nano particles are homogeneously distributed and electrically insulated within the polymeric matrix by means of one or more dispersant agents incorporated to the uncured liquid polymeric medium. This configuration avoids any aggregation of particles which consequently reduce eddy current losses. In contrast to ferrite, PBM can adapt to any form, with absolute size and shape control, as it can be mould injected or mould and pour. Furthermore, this material present recyclability in manufacturing. Acoustically, this material has great energy absorption in audible range which offers another advantage, reducing noise from the antenna.

On the other hand soft magnetic microwires exhibit excellent mechanical and magnetic properties, with high magnetic permeability, magnetic field saturation, low coercitivity and great flexibility. The extraordinary performance of this filament like material comes from its fabrication technique, rotating-water quenching. An ultrafast cooling rate of 105 Ks-1 avoids crystallisation resulting in an amorphous structure, removing any magneto crystalline anisotropy which makes them extremely soft. The diameter of this wires range between 100 to 300 microns.

In conclusion, this innovation could drastically reduce the adoption of PKE system in automotive sector and speed up new features like approach lighting and walk-away detection.


About the author:

Jorge Rodriguez is R&D Engineer at Premo – www.grupopremo.com