Design, fabrication and operation of a wireless and miniature ignition system

A wireless miniature ignition system has been developed for secure micro ignition applications. The power and data are transmitted using electromagnetic radio frequency waves between two closely coupled coils. The distance between the two coils is of 200 μm. High frequency (13.56 MHz) has been used enabling us to use coils made with PCB technology with only three copper wires with a separation between turns of 120 μm. A fully integrated prototype has been built and tested. It is 3 mm thick and has a section area close to 40 mm2 (7 mm of diameter). When the command occurs, the system assures the application of enough electrical power (150 mW) to ignite a pyrotechnical powder in contact with the resistor of the ignition system. The measured electromagnetic energy transfer efficiency is up to 50% in normal environmental conditions (air surrounded). The difference between the experimental electromagnetic energy transfer efficiency and model prediction (67%) is due to bad coupling. The implemented solution to increase the electromagnetic energy transfer efficiency is to surround the coils with a magnetic polymer: it increases the energy transfer efficiency up to 72% in the air.