Re: RF impedance matching PCB layout / analysis?

>
> I should preface this by saying I know little about RF, but have a fair
> amount of experience in a bunch of other areas, I'm not new to
> electronics but am definitely new to RF.
>
> The specific problem is transmitted power is 50dBm lower than expected
> (-60 vs. -10).  This is very likely because (due to space necessity) the
> design isn't an exact copy of the suggested RF output circuit/layout
> from the manufacturer of the balun (anaren) I'm using.
>
> Rather than getting into the details of it all, I'd like to educate
> myself in this area and do some analysis.  This issue will come up again
> for this client so it is well worth the time.
>
> This is where the piclist wisdom comes in!
>
> What I need to be able to do now and in the future is to match a given
> antenna to the RF output of the various low-power RF chips out there.
> In this case it is a TI CC2430.  So the datasheet for that chip
> specifies the differential output as being 115+J180.  TI does some
> trickery with long traces and passives to match to a 50-ohm antenna;
> this works, but is considerable board space.  Anaren makes a balun and
> has an appnote on how to use it with this part, and goes through an
> analysis of their design.  This is great, however I don't know:
>
> a) how to go from physical pcb trace shapes to the equivalent m+Jn for
> each segment
> b) the larger concept of what is going on here, and how to take each pcb
> trace segment and various caps/inductors in series to shunted to ground
> and plot them on a smith chart to wind up at 50 ohms for the antenna.
>
> Anyone still with me?
>
> I know all this is a big subject, and good software is probably big
> bucks, but tips of all sorts would be helpful.  A book (or chapter in a
> book, even), software free to kilobucks, etc.  My client has some money
> to spend to solve all this, I just don't know where to begin looking.
>
> Thanks everyone-
> J