Dear fellow researchers and Professors,
I am designing an antenna with dielectric lens. The dielectric lens is placed on the antenna to alter the radiation pattern from nearly bidirectional to mostly unidirectional.
I am working with an UWB antenna so all through the working bandwidth, the radiation pattern varies. I want to prove that dielectric lens mounting alters the radiation pattern.
Right now I have the radiation pattern plot as attached below (1st picture, at 15GHz) where it shows the changing radiation pattern, but I want more analytical proof.
I tried evaluating Front to Back Ratio on CST but because on some frequency the radiation pattern is not fully bidirectional, the FBR comes out very high value (2nd picture, at 33GHz).
Can anyone please help me with this? Any ways I can prove that my dielectric lens work as it should? Here I attached some of the varied radiation pattern and the FBR over Frequency graph from CST.
Thank you in advance.
Plot maximum gain instead of front to back ratio. Gain is directivity times efficiency. The efficiency should only vary slowly with frequency so the maximum gain should show the improvement in directivity.
Malcolm White Thanks for your answer, Sir.
I tried plotting the Max Gain over frequency and it does shows how the lens improved the radiation pattern. Can you please tell me why I can't use FBR in this case? Is it because of the not fully bidirectional pattern?
The radiation in the back direction is not well defined - you could have a null or a peak, so the ratio of front to back is totally arbitrary.
In addition you can use the ratio of the TOTAL forward radiated power to the TOTAL backward radiated power.
This can be accomplished by integrating the radiation pattern in in the each direction the forward and the backward. You will get the required proof. I see this with my eyes as the effect of the lens is clear.
Best wishes
While the initial antenna (w/o the lens) is neither "nearly bidirectional" nor omnidirectional (it somewhat favors the angles of 15° and 165 ° left @ 15 GHz, then developing 4 somewhat prominent lobes @ 33 GHz), the change of behavior due to the lens (favored direction 180 ° with newly 20 (?) dBs of gain) is obvious.
For the comparison of the operation with/without lens, the polar diagrams you already provided are "how it shoul/could be done". Provide some more plots for other frequencies - and change the scaling to a 0 - 360 ° !!!
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