Automotive Wireless Key

One of the actual trends for automotive companies is the development of smart systems in the mobility field, which aim to increase the Customer’s user experience.

Our clients requires support for the RF design and simulation of a wireless key system working at low frequencies for automotive applications, which allows the opening and starting of the vehicle (PEPS System)

Working closely with customers staff, sharing the design choices and providing all the knowledge of its employees involved, arimas provides a Project Management Support as well as all the activity of PLANNING and SIMULATION.

Project Description

PEPS system enables hand-free interaction with the vehicle. It allows the driver to lock/unlock the vehicle doors and to start/stop the vehicle engine without performing any manual action either with the key fob or a mechanical key

The operating principle based on RFiD technology, the antennas work at LF frequencies and the system consists of a number of TX antennas, some positioned inside and others outside the passenger compartment

The chosen antennas are coil with ferrite core and are connected to a matching network for the adaptation to the chosen transmission frequency

The RX antenna is represented by the key, it is totally passive, and consists of a system composed of several coils

After the design of the antenna system, the request from the customer, concerns the possibility of creating maps of the distribution of the field transmitted by the TX antenna in a grid of points around the vehicle

The project was developed using the best EM simulation software for antenna design and field map creations

System Overview

According to the requests provided by the customer, the main objective of arimas was to acquire some knowledge of the most advanced research of RFiD systems for automotive applications, from which to start the development of the antennas and study the distribution of the electromagnetic field.

We have established modeling and simulation of the system, and select the appropriate boundary conditions, mesh options and that the most influencing elements in the propagation of the magnetic field.

This assumption implies that total attenuation will be the superimposition of the effects due to power-distance relation and other effects due to the vehicle.

Through Computational Electromagnetics (EM) simulations, the antenna response was understood and allowed to perform various studies rapidly with the change of the antenna parameters for optimal performance.

We obtained the distribution of the three-dimensional vehicle electromagnetic field affected by the antenna, and analyze the local electromagnetic field distribution in the critical regions.


Finally, after analyzing and optimizing the system, through the simulations in the various propagation scenarios:

      • System in free space
      • System with presence of a vehicle
      • System with presence of a vehicle and obstacles between the transmitter and the receiver

These 3D maps of electromagnetic distribution fields data was used for localize the fob as being either inside or outside of the car. If the system determines the fob is outside, it unlocks the door. If the system senses the fob being inside the car, it starts the engine.



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