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PICDEM™ Z 2.4 GHz RF Card

FIGURE C-13: IMPEDANCE OF THE PCB ANTENNA WITH VOLTAGE STANDING WAVE RATIO

The most critical part of maintaining proper impedance is adhering to the specified

dimensions of the printed circuit board antenna (see Figure C-14). The antenna dimen-

sions, if altered, will change the specified impedance. As an example, a 1 mm variance

will shift the impedance by 5-10 MHz.

FIGURE C-14: PRINTED CIRCUIT BOARD ANTENNA DIMENSIONS

(1)

Figure C-15 and Figure C-16 illustrate simulation results of this PCB antenna. Note the

simulation results are very close to the measurements.

Note: This part has been simulated using a HFSS™ simulator by Ansoft

Corporation.

1.0

0.72

3.37

0.85

0.5

3.82

4.2

6.6

4.3

1.2

1.3

3.8

5.3

8.6

22.0

1.2

6.0

1.54

0.5

9.6

2.0

6.6

Note 1: Dimensions are in mm and tolerance is +/– 0.05 mm.

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Microchip Technology Zena Guía de usuario Pagina 39