Transmission line terminating at high impedances--suggestions? 1

[tlmassey]

Hi,

I'm working on an RF (~500 MHz) impedance transformation circuit. On the chip side of the circuit, I have a 3cm microstrip transmission line connecting the 50k ohm-impedance chip to the 50k ohm-impedance side of the transformation network. The characteristic of impedance of the line is (within a factor of two or so) bound to 150 ohms.

My question is this:
Are there any tricks that I can use to make the transmission line look less like a transmission line or otherwise improve the signal coupling to the chip?

My limitations:
1) The chip is provided by another group, and cannot be changed. I'm stuck with the high impedance and small package.
2) I can't shorten the transmission line by moving the components closer, because the chip is too small to fit eight inductors and other components.

Thanks in advance for any help that you can provide!

-TMassey

 

[nbucska]

Looks like the efficiency is not important, so we may try
something else:

Increase the power and terminate the line with Zo.
If the level has to be measured across the input,
make a resistive divider (or "T") with Zo input impedance
and the effect of the loading on the response can be calculated.

The sweep is evidently wide band, which makes the
proper termination difficult. If this is only for measurement an other solution would be to terminate
the line w. Zo, and add a buffer amplifier NEXT to the
DUT.

By the way in my 30+ yrs I learned that when a problem
is difficult, perhaps you can step back and you
may find an other way, so you don't have to solve it
at all...






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