- Thu Aug 16, 2007 1:28 am
#33774
Hi GPS guys,
sorry, this might be a completely stupid question, but I am not a HF person at all. So my apologies ahead
I am thinking of reducing weight to the smallest possible, thus using the tiny GPS chip scale antenna. The data sheet talks about a "50 Ohm micro strip" input... What is this? A PCB trace that has 50 Ohm resistance? At what frequency? How do I design that? Is there a rule-of-thumb?
Also, people have recommended using an LNA (e.g. RF Micro Devices RF2373) to amplify the antenna-signal. Does this go *before* or *after* the 50-Ohm strip? In the data sheet (http://tinyurl.com/2ahxeb) on page 4-5 they show an example circuit, but it's not clear to me how this interacts with the 50Ohm trace... Is such a "complex" circuit required at all? Can I 'just' use the amplifier?
Ideally, I'd just have a tiny GPS modul (about 3grams) and LNA+passive antenna <0.5grams)... HELP ... please
Or does anyone have a very simple design example? Doesn't have to be perfect.
Thanks a lot!
Jorg
sorry, this might be a completely stupid question, but I am not a HF person at all. So my apologies ahead
I am thinking of reducing weight to the smallest possible, thus using the tiny GPS chip scale antenna. The data sheet talks about a "50 Ohm micro strip" input... What is this? A PCB trace that has 50 Ohm resistance? At what frequency? How do I design that? Is there a rule-of-thumb?
Also, people have recommended using an LNA (e.g. RF Micro Devices RF2373) to amplify the antenna-signal. Does this go *before* or *after* the 50-Ohm strip? In the data sheet (http://tinyurl.com/2ahxeb) on page 4-5 they show an example circuit, but it's not clear to me how this interacts with the 50Ohm trace... Is such a "complex" circuit required at all? Can I 'just' use the amplifier?
Ideally, I'd just have a tiny GPS modul (about 3grams) and LNA+passive antenna <0.5grams)... HELP ... please
Or does anyone have a very simple design example? Doesn't have to be perfect.
Thanks a lot!
Jorg