[Need Advice] Negative gain in HFSS simulation
I am a beginner in using HFSS.
Need your kindly advice and assist if you don't mind.
Currently I'm designing a printed antenna using HFSS, this figure show the antenna structure and geometry:
The problem is the simulation give a negative gain as the result.
I am sure there a mistake in my design (project file) and not in the antenna structure or dimension, because this antenna has already mass fabricated and being used world wide. I just simply use its structure and dimension to check while deepening my understanding in using HFSS.
Please find my HFSS simulation file, hopefully somebody could download and check it. And let me know, where did I get wrong.
Btw, what is the name of this antenna? I just name it printed folded dipole antenna. cmiiw.
Thank you in advance.
What is happening is that the radiation efficiency is low. This is acceptable as a tradeoff for physical size. It is made up for in more RF amplifier output power. In many applications there are government maximum radiated power limits and so the inefficient antenna is combined with a higher power amplifier.
For instance, mobile telephones used near human bodies have something like 1W maximum power radiated limits. Since these are TDMA or similar pulsed applications, and they receive most of the time, the battery life is acceptable.
In applications such as unlicensed types that have microwatt radiated limits, the size-efficiency tradeoff is acceptable. So what if it takes 1 mW of RF power to get the few uW of radiated energy. The rest of the system, such as uP, consume more than that.