Source

Type

Designation

Uncertainty (±)

Contribution

Standard uncertainty

Sensitive factor

Standard uncertainty

Relative amplitude accuracy of Spectrum analyzer

B

0.6 dB

Rectangular

0.173

0.5

0.173

Signal generator amplitude stability

B

0.1 dB

Rectangular

0.058

0.5

0.029

Impedance mismatch of Spectrum analyzer and antenna

B

0.027 dB

U-shaped

0.019

0.5

0.01

Impedance mismatch of Signal source and antenna

B

0.157

U-shaped

0.111

0.5

0.055

Site shortage

B

0.307 dB

T Distribution

0.441

0.5

0.221

Repeatability of system

A

1

Sine distribution

1

0.5

0.5

Change of measurement distance

B

0.1 m (r = 3 m)

Rectangular

0.058 (r = 3)

4.34/r

0.084

AF combined uncertainty of log-periodic antenna

1.08

AF expanded uncertainty of log-periodic antenna (k = 2)

2.16