Hi all. I am new to this forum and I need some help for a paper I'm writing. I'm looking for a way to generate very high frequency triangle waves(20MHz+) and I'm unsure about my implementation. My research hinges on another paper by Jian Huang and this is my reference

I'm still learning and I'm very unsure about my circuit.

I'm looking about advice on how to improve this circuit or other reference schematics I can use. The circuit above is designed to generate 20MHz but I'm skeptical if i built it correctly or if it's even capable of producing this fast of a triangle wave.
Another concern of mine is that it might not be producing the triangle wave i'm looking for.

I'm worried that this circuit produces a sawtooth(bottom, cyan) but the paper calls for a triangle wave(top, green).
I'm thankful for all the advice i can get!

 

The circuit needs one comparator and one op-amp, not two comparators. With R1=R2 you get a triangle wave. As R1 or R2 tends towards zero you get more of a sawtooth.

 

Alright, i fixed that. Anything else i should be aware of or is it good to go?

 

The circuit you have is for a bipolar trianglewave. i.e. it is centred on 0V. For that your op-amp and comparator need positive and negative supplies.
If you only have a single supply, connect op-amp non-inverting input and comparator inverting input to half the supply (use two equal value resistors to produce a half-supply reference)

 

Got it. I did some other quick fixes, though i wonder if 10k divider resistors are too high

 

It appears that Jian Huang leaned heavily on SLAU508 but then forgot to include it in the references.

The AD3081 has a slew rate of 30V/us. Depending on the amplitude you want that may not be enough.