snip
>I fail to understand your point. What do you mean by the 3 dB down point?
If you mean the 3 dB points in a filter (which is essentially what a
matching network is), that is something completely different. I assume
that's what you mean so I'll address that.
>
>The 3 dB down point in a filter is typically what is used to specify
bandwidth. That 3 dB down level is basically the level where the magnitude
of S21 is 3 dB below that of its maximum value (minimum loss). At the 3 dB
points, half the power that is transmitted at that frequency by the source
or whatever, gets passed through to the load or whatever is on the other
side of the filter.
>
>So where does the other 3 dB go? Is it dissipated? Hardly. To understand
where it goes, one must look at the magnitude of S11 and S22 of the filter.
At the 3 dB point, the values of S11 and S22 are getting large and all of
that power is being REFLECTED back towards the source. In fact for the most
part at the 3 dB point, S11 will typically be such that half the power at
that frequency won't even get beyond the input of the filter.
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.
Steve
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