"Scott Stephens" wrote in message
news:hDWqc.26611$gr.2415597@attbi_s52...

I'm thinking I should try a binary weighted series-L shunt-C ladder
network, with varactors for the C. Could switch the varactors into
forward conduction to tune out the end of the line, raising the frequency.

I played with that idea on the simulator. Didn't seem to have
a lot going for it.


Latest Microwave News describes a nonlinear ceramic (BaZrTiO) thin-film
voltage-tuned capacitor. I've read about articles that use common
ceramic caps as VCO's, even the capacitor-equivalent of magnetic
amplifiers. The advantage of thin films is you can fabricate
voltage-tuned filters, as well as individual caps.

I've been following those nonlinear ceramics (ie BST) for years. They
don't seem very promising as a tuning diode replacement. The Q is too
low, the tuning range is too restricted, and there are temperature problems.

Rick N6RK