Circular patch model problem (HFSS)
I'm designing a TM21 circular patch in HFSS. To get circular polarization I designed a branch line coupler to feed the antenna.
First I designed branchline coupler, than the antenna and at the end I have to place the antenna on the coupler.
Coupler model and antenna model are correct and they give good results, but I can't connect coupler to the antenna. In theory it should be ok, but HFSS give the results as if antenna and coupler were not connected. It seams like the coupler is radiating, not the antenna.
Could you take a look at the model (in attachment) and tell me what did I do wrong?
Thank you
Hi Vfurlan,
After simulating your model, it showed that the AR of your antenna around 1.6 GHz is larger than 3dB but not very high.
According to my experience the face that wave port should be defined on should bear the diemesion of 11*w and 10*h. W is the width of MS line and h is the substrate thickness. Your port face is a little small.
For the feeding part, maybe the extended ms line on the output port of hybrid should be truncated, which may affect the field distribution in antenna's substrate. Moreover, with further adjust of feeding position, a desirable AR should be observed.
Added after 28 minutes:
By the way, after reviseing your port's dimension, the axial ration at 1.5 GHz is 2 dB.
Is that desirable?