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Design >> RF Design >> Matching to Internal Antenna
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Message started by aaron_do on Oct 29^th, 2012, 1:09am

Title: Matching to Internal Antenna
Post by aaron_do on Oct 29^th, 2012, 1:09am

Hi all,

I have checked that for a mobile phone internal antenna, a reasonably good VSWR seems to be around 3:1. Since the PA is normally designed to drive a 50-ohm load, does this mean that most handsets these days feature a broadband match between the cellular switch and the antenna? If so, how is it normally implemented? LC matching?

From what I've been reading, the antenna's performance is very sensitive to its surrounding environment, so it seems that the manufacturers need to first develop the floor plan for the RF front end and then design the matching based on the best performance. Does that sound right?

thanks,
Aaron

BTW, I realize I probably shouldn't be using the word matching since it isn't really impedance matching...

Title: Re: Matching to Internal Antenna
Post by loose-electron on Oct 31^st, 2012, 9:33pm

There is usually an LC network between the antenna and the RF PA.

Also the polar plots for the antenna need to be re-run in the phone environment because component placement in the phone does affect the radiation patterns.

There are many vendors of ceramic and (and other) substrate based antennas out there.
Take a look at their application notes for ideas on LC networks to the PA.