how to construct a uhf antenna
I m a new in this forum and I don't know much about designing antenna.
Does anybody have an idea how can I construct a Patch antenna that have a wide band in the frequency range: 0.6GHz till at least 2GHz, with a highest gain possible??
Thank u for your help:D:
I know antenna UwB operate in frequency (3.1-10.6 Ghz). other in frequency (0.2-2 Gb) isn't interested in UWB system.
Spiral antennas usually yield a very good bandwidth. Look into the following document which discusses a few such antenna structures:
J. Powell, Antenna Design for Ultra Wideband Radio, Ph.D. thesis, Massachusetts
Institute of Technology, 2001.
If you are interested in a archimidean spiral, I can give you a model that I designed in HFSS.
thank you for the book mprathap. It s very helpful
if you could send me the dimension of the archimidean spiral, it would be perfect, I can simulate it on CST microwave.
Sorry for the delay. These are some architectures for UWB antennas. I am not sure if you can use these as it is right now, since I made these files long ago and I may have played around with them after that and left them in an 'unmatched' state. But these designs should get you started.
I agree with mprathap. Patch antennas resonate at λg/2, where λg is the guided wavelength. At UHF frequencies this leads to physically large antennas. You can miniaturize them by using high dielectric substrates, but then you will lose efficiency and bandwidth, and it will be harder to impedance match.
At lower frequencies usually meandered loop antennas are used. For ultra-wideband you need to switch to spiral antennas. You can think of spiral antennas as cascaded loop antenna sections, of which resonant frequencies cover your entire bandwidth.
You can take a look at Balanis antenna book: frequency independent antennas and antenna miniaturization. But, the best resource is: Antenna Engineering Handbook 4th ed.
Patch antennas with the bandwidth you desire (about two octaves) are probably not practical. I would consider other alternative.
I managed to get 50% out of a patch but it took some effort.