I have a GSM Modem that works on 2300MHz Frequency (LTE), but it could only receive 3 bar of signal strength. I plan to make a DIY directional antenna that is made specifically for this Frequency spectrum. From the online search, I found that people can make antenna either for 2.4GHz or 5GHz using the same material, same shape, but with a different measurement. So, my understanding is that we could make an antenna to work on a specific frequency by changing the measurement of the element. -- I am thinking about DIY bi-quad antenna --. Will it work?
Another thing that is kind of related to my question is that, This modem not only works on 2300MHz but also work on other frequency as well. Just like a cell phone. This modem, depending on what network carrier I use, also changed its frequency based on the frequency used by that mobile provider or carrier. Let say that 5 mobile network operator/Carrier in my country work on 850MHz, 900 MHz, 1800MHz, 1950MHz and 2300MHz. How the internal antenna work on all of those frequencies, are they using 5 different antennae inside of the device or they can use one antenna that works on all of that frequency spectrum?
By making one specific antenna for each one of those frequencies spectra will it improve the signal quality received by the modem?
I assume that the manufacturer of such device makes it able to receive so much different frequency is so that the device can be compatible with every mobile carrier, not necessarily because that the internal antenna inside the device is able to work on that wide range of the spectrum. I think by making a specific antenna for one specific frequency could improve the performance of the device.
Please do correct me if there are a lot of mistake in my way of thinking and my understanding of the matter. I just wanted to learn. :)