
Coreless coils are frequently used as antennas for RF data transmission. When frequencies in the range of 1 kHz to 900 kHz are used, these antennas are wire-wound with selfbonding wire. The most typical application is the use in transponders, keyless systems, identity cards, antitheft tags, etc...
Sensors also use these inductors, both for inductive such as proximity sensors, etc. as well as reluctance change sensors like the ones used in electronic coin validators.
The last significant application field is linear motors where the coil resistance must be exactly controlled by a perfect winding technology.
Contactless ISO cards, which transmit data via radio is the most exigent application as the thickness must be very small.
When used as RF data transmission antennas, the function is the same than the ferrite wound transponder inductor but here, we have the advantages of a non-ferromagnetic core thus avoiding saturation problems. Therefore the current handling capability uses to be higher than in a ferrite coil but the space distribution of the magnetic field is more spherical as well.
PREMO coreless coils are manufactured with fully automatic tailor made machinery in which sizes and shapes are easily changed, thanks to an inexpensive tooling system. This way, we could ramp up from prototype to mass production in 4-6 weeks.
