FEKO simulation warnings

[MrElec]

When i simulated a Microstrip Grid Array Antenna by using FEKO, i've got these annoying warnings :

1- WARNING 594: Due to rounding errors the solution may be totally invalid.
I've changed to double precision but it was with no result.

2- WARNING 1681: Matrix is numerically singular, solution very critical.

3- WARNING 3843: Directivity is not defined because the radiated power is equal to the power loss.

I can't figure out what are the causes of these problems and how to solve in FEKO?

I attached my project in order if someone can help.

 

[soundav]

May I know which version of FEKO you are using so i can see if i can run in my system

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Hi MrElec

Warning 594 : This may be due to small electrical size of your design and/or your frequency is too low.

 

[MrElec]

Thank you for response.

I'm using Altair CadFeko 14.0. I'm trying to get the results of this article :"Analysis And Synthesis of Millimeter-Wave Microstrip Grid-Array Antennas". The radiator works at 60 GHz.

Width of all the strips is small 0.1 mm and the length is 2.84 mm.

 

[soundav]

Hi Mr. Elec,

You said the model is designed to work at 60GHz but in your model you have given the working range as 50 - 70Hz. change the freq min and max to 50e9 and 70e9 respectively.
and then you are working in mm dimensions so your lambda value should be c0/freqmax*1e3

Try this out.