Measuring Mutual impedance of 2 antennas

Hello All,

How do I measure the mutual impedance of two patches using network analyser?

Thanks in advance.

If you are referring to mutual coupling, I would expect a Sxy value rather than an impedance. As any transmission path, it can be measured by two port method, and as with any antenna measurement, you have to consider cable effects.

Could you please explain or give me a reference to know more about two port method?

I suggest VNA user manuals and additional manufacturer literature, e.g. from Agilent.

I guess mutual coupling and mutual impedance are two different phenomena. I m wrong?

The mutual impedance is determined by subtracting the input impedance of the single patch from the input impedance of the patch with the other patch. 1 port measurement should be ok.

According to the definition in text books, the mutual impedance could be calculated from two-port S-parameters. Mutual coupling would be just another representation of the same data, I think.

Determining the mutual impedance as a one-port measurement requires, that the impedance of a single element has been measured in absence of the other before. Also the mutual impedance has to be calculated. Thus I assume a two port measurement as more reliable. In any case, the mutual impedance is a kind of virtual parameter, that can't be directly measured and is strongly affected by a varied antenna port reference plane.