How to design an antenna on a PCB

AN2972

12/25

Doc ID 15629 Rev 6

2.3

Inductance of a square antenna

, where:

●

●

●

K1 and K2 depend on the layout (refer to Table 2 for values)

Figure 10. Square antennas

2.4

ST antenna calculation tool

ST provides a simplified software tool (

antenne.exe) to compute inductances of rectangular

planar antennas. The purpose of this tool is to give good approximations: the obtained

results should be verified.

This tool uses the Grover method (see Equation 1). Figure 11 shows the user interface.

Equation 1: Grover method

, where:

●

M is the mutual inductance between each of the antenna segments

●

Equation 2:

, where:

●

s is the number of segments

●

Table 2.

K1 and K2 values according to layout

Layout

K1

K2

Square

2.34

2.75

Hexagonal

2.33

3.82

Octagonal

2.25

3.55

L

ant

K1

μ

0

×

N

2

×

d

1K2 p

⋅

+

-------------------------

×

=

L

ant

L

0

M



+

=

L

0

L

j

j1

=

s



=