Because of the high maintenance needed to monitor and filter spammers from the RF Cafe Forums, I decided that it would
be best to just archive the pages to make all the good information posted in the past available for review. It is unfortunate
that the scumbags of the world ruin an otherwise useful venue for people wanting to exchanged useful ideas and views.
It seems that the more formal social media like Facebook pretty much dominate this kind of venue anymore anyway, so if
you would like to post something on RF Cafe's
page, please do.
Below are all of the forum threads, including all
the responses to the original posts.
Post subject: microstrip feed line
Posted: Thu Dec 29, 2005 6:11 pm
Joined: Mon Nov 21, 2005 3:30 pm
i ask you why the almost microstrip line used as the feed line for the patch antenna are 50 Ohm? i ask you also if we can use other 74 Ohm feed line excitation for this antenna?
thanks for your help....
Posted: Fri Dec 30, 2005 10:27 am
Joined: Thu Jul 28, 2005 6:18 pm
If your antenna impedance is 50 ohms, you'll want to feed it with a 50 ohm microstip line or you'll have some mismatch loss reducing the efficiency of your antenna. Another reason to use 50 ohms is that, presumably, at some point you're going to solder some type of coax or coaxial connector to the microstrip. The majority (if not all) of the cables and connectors used for this purpose are 50 ohms.
Now, you could certainly feed the antenna with a 74 ohm microstrip line, but you would have to design the patch to have an impedance of 74 ohms. This isn't the convention and I've never done it that way so I can't tell you how feasible it is.
Posted: Fri Dec 30, 2005 5:55 pm
thanks, so please can you tell me how we can determine the input impedance for the UWB antenna, so here we have a broad band frequency, and we know that the input impedance is calculated for a single frequecy. i ask you please to explain me this problem & send me if you have some theoretical doc. thank you very much
happy new year for you and for all our freinds on the rfcafe forum...