How to deal with Unexpected result of antenna performance?
I would like to raise a question which is about how to manage the unexpected result.
If we are designing antenna, say tri band antenna, then designed it, but PCB still not come back yet. Then make prototype first, to measure the prototype with calibrated cable and metal sheet (dimension same as PCB) for ground plane. Having seen slightly different result (S11 or VSWR result), we put Back case on the back of antenna, the frequency shifted slightly. Then, if we hold the case, frequency shifted again.
Then, after all, the antenna mounted on PCB, we finally found that antenna is mismatch after PCB trace, we put on the matching network..... finally, everything done....
Here, I am curious about how could I ensure the antenna having a great efficiency after several shift or mismatch. I really would appreciate if anyone could share this experience in this forum.
Best Regards,
Le
This problem is hard to be understand not only by non-experienced engineers, but also people with a lot of experience in RF cannot believe that after years of study and working with EM simulators, they have to tune and re-tune manual the antenna when minor changes appear in the design. Is part of the beauty of RF.
One indication is to put in your simulation all these factors that de-tune the antenna (PCB materials, ground, hand-holding, human body, plastic case, etc), and try to find a compromise between performances.
A simulated loaded antenna will behave better than a free-space simulated antenna, when is build as a prototype.
Dear Vfone,
i agree, it is beauty of RF. Thanks for your advice and sharing. And, nice to meet you in this forum
Regards,
Le