Varactor voltage in high performance VHF VCO?

[rf-fil]

I'm working on a thing, and got to modeling VCOs, to find one that would be good for VHF, specifically a few MHz around 124MHz. All of the topologies have one thing in common. Fundamentally, low phase noise VCO requires high loaded Q resonator. Which means high voltage across it. which would mean, high RF voltage across the varactors. I've attached one example circuit. In my example, the voltage across the top of the resonator is ±20V (!!), and about ±4V across the varactor.

So it seems like my only choice is to reduce the voltage across the resonator either by reducing the loaded Q, or by using smaller DC bias current. am I right?

[paul@yahrprobert.com]

So that capacitor C4  in series with your varactor drops some of the RF voltage.  If you make that smaller you can reduce the voltage on the varactor.  That might reduce your tuning range, so further information is needed.

[duak]

You might be able to make two varactors work in a push-pull configuration where the bias voltage across one increases while it decreases across the other.

One way is something like the attached screen shot from page 47 of Turner's ABCs of Varactors: https://worldradiohistory.com/BOOKSHELF-ARH/Author-Groups/Rufus-Turner/ABC%27s-of-Varactors-Rufus-Turner.pdf.

I envisage something a bit different - see PP varactors.jpg attached file. The 100k resistor isolates the control voltage driver from the resonant circuit.  The two 1M0 resistors balance the average bias voltages.  This requires a higher bias voltage but it offers a greater capacitance because the varactors are in parallel.

I think I've seen a circuit using two varactors and a center tapped inductor, but I doubt it could be applied here.

Cheers,