Electric field strength measurement using antenna factor of loop antenna

A handheld spectrum analyzer and a loop antenna enable the easy measurement of the electric field strength from 50kHz to 30MHz.

Application

[Connection block diagram]

Figure:Spectrum AnalyzerMSA438とLoop antennaを接続する

Solution

By using the antenna factor of loop antenna MAN120, the electric field strength from 50kHz to 30MHz can be measured with handheld spectrum analyzer MSA438.

The electric field strength is calculated from the following equation.

Er = Pr +Af + 107

However, Er:electric field strength [dBuV/m], Pr: receiving power [dBm], Af: antenna factor [dB/m]

The typical value of the antenna factor of loop antenna MAN120 is as follows. This antenna has received the A2LA accreditation calibration.

Frequency [MHz] Af [dB/m]

0.05 70.8

0.07 67.9

0.1 65

0.15 61.6

0.2 59.2

0.3 56

0.4 53.9

0.5 52.6
Frequency [MHz] Af [dB/m]

0.6 51.4

0.7 50.7

1 49.2

1.5 48.2

2 47.5

3 47.3

4 47.1

5 47.1
Frequency [MHz] Af [dB/m]

6 47.2

7 47.4

8 48.1

10 47.4

15 47.3

20 47.5

25 46.9

30 47.1

Frequency [MHz]	Af [dB/m]
0.05	70.8
0.07	67.9
0.1	65
0.15	61.6
0.2	59.2
0.3	56
0.4	53.9
0.5	52.6

Frequency [MHz]	Af [dB/m]
0.6	51.4
0.7	50.7
1	49.2
1.5	48.2
2	47.5
3	47.3
4	47.1
5	47.1

Frequency [MHz]	Af [dB/m]
6	47.2
7	47.4
8	48.1
10	47.4
15	47.3
20	47.5
25	46.9
30	47.1

System configuration

This system is an inexpensive tool by which the elctric field strength can be easily measured.

3.3GHzSpectrum Analyzer [MSA438]	x 1
MSA438 calibration set	x 1
Loop antenna [MAN120)]	x 1
BNC cable (1.5m) [MC314]	x 1
Adapter N(P)/BNC(J) [MA307]	x 1
Adapter N(J)/BNC(J)	x 1