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Axial ratio and cross polar discrimination (XPD) interference

For circular polarisation the purity of the polarisation is specified in terms of axial ratio.

To obtain the cross polar discrimination (XPD) interference refer to the following formula:

XPD = 20 log ((r+1)/(r-1)) dB.

Axial Ratio AR (dB)	Axial Ratio r (number)	XPD (dB)
0.3	1.0352	35.24
0.34	1.04	34.15
0.42	1.05	32.26
0.51	1.06	30.71
0.59	1.07	29.42
0.60	1.0714	29.25
0.67	1.08	28,3
0.75	1.09	27.32
0.83	1.1	26.44
0.98	1.12	24.94
1.01	1.123	24.74
1.06	1.13	24.29
1.14	1.14	23.69
1.21	1.15	23.13
1.36	1.17	22.12
1.58	1.2	20.83

Last amended 18 Sept 2021.