Planar Near-Field Measurement Using Dipole Probe

Altair Forum User

At this moment I'm using the Student Edition. I want to do a planar near field measurement using a dipole as the probe and gather the near E-fields.. However, I'm having difficulties to come up with a correct method.

 

I tried to generate a near field radiation pattern of an dipole. Then requesting the (RX ANTENNA NF) with the AUT, but then I only get the received power in 1 point and there seems to be no easy way of converting or requesting this to/at multiple points on a planar measurement area. The parameter sweep doesn't work because of critical errors when merging.

 

What would be the best approach to my problem?

 

Thank you in advance for your time.

 

Altair Forum User

It is possible to have multiple RX Antenna NF requests in a single configuration, i.e. you can define an RX request at each position that you would like to measure the field. Note that it is not necessary to define a new field data structure of the dipole for each request, you only need to do this once and can reuse it for each RX antenna request. 

In principle your idea with the parameter sweep should also work, perhaps you can provide more detail about the error message.  

Altair Forum User

Thank you for the response.

 

I've looked into the error and came to the conclusion that CADFEKO generates labels such as: VoltageSource1@1, VoltageSource1@2. However, when using the parameter script, this '@' icon will lead to an invalid label. I've modified the script to work by removing the '@'. This did the trick and gave me a complete run of the parameter sweep but here I only got received power, but no phase information.

 name = string.gsub(string.gsub(string.format('%s_sweep',ii), '.*%.', ''), '@','')

Next, I also looked into having multiple RX Antenna NF requests as you suggested. It is indeed possible to define multiple NF requests, however this has to be done manually in CADFEKO. For this problem, I used EDITFEKO to create a simple for-loop to sweep to all the needed X and Y positions. But the RX Antenna NF doesn't seem to work when making use of dipole with a load. Again, no phase information, only magnitude. 

 

Last I tried to use EDITFEKO to make a dipole with a wire port. I can make a line and add a 0V voltage source. But it seems not easy to create many dipoles as big as the scanning size. I'm using half-wave dipoles and half wavelength spacing, but that leads to overlapping segments.