on 5/25/01 8:47 AM, Steve Thompson at g8gsq@qsl.net wrote:
> For power to be reflected, doesn't the source have to be a transmission
> line? A series C can reduce the power delivered to a load just by adding
> reactance and increasing the overall impedance thus reducing the current.
What do you mean "doesn't the source have to be a transmission line?"
A series C can indeed do what you say. However, a true series C does not
dissipate energy but stores it.
I was speaking in terms of the concept of the pi tank circuit being a
filter. This it is. A filter is a two port network. For that matter, a
capacitor is a two port network.
Any two port network can be defined in terms of S parameters. Therefore, it
will have S11, S21, S12 and S22. S11 is defined as reflection coefficient,
etc. etc.
Think of it another way. At microwave frequencies, transmission line
elements act as capacitors. So can't a capacitor therefore be seen to have
transmission line characteristics at lower frequencies? I could build a 1/4
wave stub at 14 MHz and match with it if I wanted to and it would look
capacitive.
The fact is, we are both right, but looking at the same thing from different
perspectives.
73,
Jon
NA9D
-------------------------------------
Jon Ogden
NA9D (ex: KE9NA)
Member: ARRL, AMSAT, DXCC, NRA
http://www.qsl.net/ke9na
"A life lived in fear is a life half lived."
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