Non-contactless (contact) measurement method

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Non-contactless (contact) measurement method

This section describes a non-contactless verification method of antenna coil prototypes. The

results presented here are based on a short-range (SR) tag antenna initially designed to

have the following characteristics:

●

Antenna dimensions: 38 mm × 38 mm (A3)

●

Tuning frequency: 14.4 MHz

6.1

Without an analyzer (second method)

Equipment needed:

●

Signal generator

●

Oscilloscope

●

Reference capacitor

●

Loop antenna

The equivalent circuit of the antenna coil can be determined using the appropriate

measuring instruments (see Figure 18) and following the instructions described in

Section 6.1.2.

6.1.1

Preparing the equipment and connections

The reference capacitor simulates the presence of the chip. Connect it to the coil using an

appropriate test fixture (to generate as little interference as possible). The coil is now ready

for measurements.

To make the analysis, connect a second ISO standard loop antenna (see Figure 14) (with a

50

Ω input resistance) to the oscilloscope, and place it in the field generated by the first loop

antenna as shown in Figure 18.

Figure 18.

Measurement circuit

The measurement circuit is now operational.

Oscilloscope

250 Msamples/s

47 k

Ω

ai15822

Signal generator