The sensitivity distribution was measured for the above sensing entry, W300 mm x H100 mm, by applying 50 kHz and using Fe test ball of 1.2 mm diameter as shown in Figure 15(a).Two small copper plates on center of receiving antenna coil
, in horizontal direction, were patched to compensate sensitivity in sensing entry by providing more electromagnetic flux linkages.
Hence, the induced voltage of the balise antenna coil
is expressed as
The magnetic moment m (m = N * I * A) created on axis in an air core system is proportional to the number of turns N of the antenna coil
, the area A ([m.sup.2]) of the coil and the current I (amperes) flowing through it.
With HF RFID, the reader powers the tag via the magnetic field generated by its antenna coil
. It will power the tag only when the plane of the tag's antenna coil
is parallel with that of the reader's.
"The antenna coil
is what transmits the signal, you don't need a battery" Michael McAlpine, the team's principal investigator, said.
Whatever the outcome of these full-body scanning evaluations, it is clear that the abdominal threat does not require the same magnitude of antenna coil
sizes or power as may be needed for other QR applications.
Therefore, they are placed in a small round silicone envelope that has a central opening and an overhanging rim; the envelope is situated in the center of the antenna coil
. In our 2 patients, the direct external force of their respective falls probably dislodged the magnet from the envelope, resulting in the migration of the magnet toward the receiver-stimulator part of the device.
The sensors are comprised by a spiral induction (L) antenna coil
and a plate or interdigitated capacitor (C) that is in contact with the quantity to be measured.
A contactless smart chip module contains a memory module and an antenna coil
, located inside a card, allowing the chip to communicate with an external antenna.
The oscillation frequency depends on [C.sub.06], [C.sub.07], [C.sub.08] and [L.sub.01], and the layout of the antenna coil
By adding up to three antenna coils
, a microcontroller, an RF transmitter or transceiver and a battery, a complete, hands-free key fob for PEG systems can be designed.