# How to measure antenna gain using network analyser ?

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#### yuen_cityu

##### Junior Member level 3
Hi all,

is it possible to measure the antenna gain using network analyser?
Could i use two identical antenna connected to network analyser and measure it S11 and S12 , then calculate the antenna gain?

Thanks a lot

#### dowjones

##### Full Member level 2
there is a method to measure the antenna gain called "Purcell method", which involves a single antenna looking at a reflecting plane in front of it. From S11 measurements you can extract a line and the slope is proportinal to the gain.

If you have access to IEEExplore look for that. There are several papers on it , for instance,

Z. Wu, "Effect of Mismatch on Antenna Gain Measurement by Purcell's Method," Electronics Letters, vol. 22, pp. 522-524, 1986.

I dont know any method measuring S21 between two antennas, although probably you may think of something varying the distance between antennas.

regards

#### nec3

##### Junior Member level 3
It is possible to measure the gain of any antenna by using a network analyzer only if you have a "very reference" izotropic antenna which has a gain of 0 dB or some thing you are sure of, that you take as a referance.
I tried the second way since i did not have a perfect isotropic antenna and compared to each.
i first connected the two of antennas which i considered as reference to the ports of ntw analyzer and measured gain.Then changed one of them with the antenna that i wanted to calibrate.and measure again.

below may help

#### mrm

##### Full Member level 1
Can someone attach something more about Purcell Method?

mckinson

### mckinson

Points: 2

#### yuen_cityu

##### Junior Member level 3
Thanks a lot !!

I have found the paper relating to Purcell method for antenna gain measurement. Attached, pls find it below.

Points: 2

### Trevelon

Points: 2

#### mckinson

##### Full Member level 2
antenna gain measure ,compare the signal generator .

Points: 2

### Carlosrrf

Points: 2

#### dowjones

##### Full Member level 2
hello again,

find attached two more references of the method. I hope they are useful to you. sorry but I dont have pdfs

P. Coquet, K. Mahdjoubi, C. Terret, Automatic Antenna Gain Measurement at High Frequencies. Electronics Letters July 1992, vol 28, no 14. pp 1339-1340

RQ Lee, MF Baddour, Gain Measurement of microstrip antennas under mismatched conditions. AMTA 1989. pp 4.17-4.19

regards

#### son_of_wind

##### Junior Member level 1
Greatful.

/Warning #1 - No "Thank you" messages here! (klug)/

Carlosrrf

Points: 2