5

TK5551

4709B–RFID–10/03

Measurement

Assembly

All parameters are measured in a Helmholtz arrangement, which generates a homoge-

nous magnetic field (see Figure 6 and Figure 7). A function generator drives the field

generating coils, so the magnetic field can be varied in frequency and field strength.

Figure 6. Testing Application

Figure 7. Testing Geometry

SUBTRACTOR

FUNCTION

GENERATOR

OUTPUT

VOLTAGE

AMPLIFIER

1:10

FIELD GENERATING

COILS ( IN PHASE )

REFERENCE COIL ( IN PHASE )

SENSING COILS ( IN PHASE )

REFERENCE COIL

( IN PHASE )

TK5551

30 mm

15 mm

2 mm

5 mm

24 mm

60 mm

SENSING COIL

REFERENCE COIL

FIELD GENERATING COIL

SENSING COIL

REFERENCE COIL

FIELD GENERATING COIL

TK5551