Hi,
I know that dipole length should be lambda/2. But in the attached paper the author designed a planar printed dipole array at 2.4 GHz on FR4 substrate where single element arm length 2L = 50 mm. But at 2.4GHz, half wavelength is around 30mm for Fr4 substrate. In that case, length is much higher for the this design in the paper.
But the author said the designed maintained 50% of the wavelength rule. I am not understanding how. Can someone help me to understand?
Part of this antenna is effectively in microstrip, some of it in balanced line in opposite side of the substrate, and some of it is on one side of the substrate with no ground under it. All three of these will have different effective dielectric constants and wavelengths because different proportions of the electric energy are in the dielectric substrate. If you have a simulation tool, simulate these lines to see what the wavelength is in each. See the answer Vladimir D. Burtsev gave to your other question.
Hi Manjurul Ahsan Riheen It seems like the dipole is too long for 2.4 GHz, especially on FR4. But the key is that different parts of the antenna are in different transmission environments some in microstrip (with ground), some as a balanced line on opposite sides of the substrate, and some with no ground underneath.
Each of these has a different effective dielectric constant, so the wavelength varies across the structure. What looks electrically too long in one medium might actually resonate just right when you account for all the sections together.The overall length makes sense once you realize it’s not a uniform medium, and the antenna resonates as a whole. Simulating each section can help visualize this.
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