Magnetic antennae are designed for access applications
The LFAD-series (Diabolo-shape) magnetic emitter antennae have been designed by Premo to answer the need of robustness and magnetic performance in mid-range antennae for passive keyless entry (PKE) in automotive applications as well as general RFID-LF access and RTLS applications.
Premo claims that the LFAD-series antennae provide up to 40 to 50 per cent reduction in length. Most of the LF antennae in the market measure 70 to 80mm in length for a standard range or 150 to 170mm for mid-range and 250 to 350mm for long range antennae.
Until recently, mid-range antennae, with a sensitivity around three times that of standard range versions, have become increasingly popular as they provide a wake-up distance of around four to five metres.
The antenna performance in term of mechanical robustness, resonance frequency variation versus temperature and waterproof have been the most important headache for the designers, reports Premo. This design includes a patented emitter antenna, that solves these issues, without compromising the cost, says the company.
According to Premo, the LFAD series antennae meet all the technical performance of mid- and long-range antennae without incurring expenses, or effecting temperature and mechanical performance.
Premo uses a core with a variable cross-sectional area that is minimised at the centre of the antenna where the winding is located. The antennae in the series meet AEC-Q200. They also meet waterproof specifications of the IP54 to IP69K standards due to their specific packaging (rugged plastic box filled with polyurethane resin, PA-LPM protection, combination of both materials and HPM (high pressure moulding) in PBT GF20-30 for IP69K). This construction is also claimed to provide much better drop, bending and torsion test limits.
A wide range of values from 160 to 500-microH, and antennae for 20, 125 and 134.2kHz frequency operation are available. They can be specified with or without capacitor and resistors inside.
Visit Premo at electronica in Munich, Germany (13 to 16 November) Hall B3 stand 548
