Hi, Im looking at a delay line oscillator to make a wideband vco upto 2ghz or more, it seems much more behaved than the colpits arangement I was trying before, at the moment I can get about 3:1 tuning range with just a varicap at each end of the delay line, but im looking to get as much as I can, is there any other way of connecting varicaps to extend the tuning range or maybe making the delay shorter with increasing frequency ?
Ive shaped the delay line like a hairpin and it made me think of a trombone if only I could slide the thing somehow but electrically with say varicaps.
Alternatively what would be the best way to use voltage controlled switches to switch the length ? I have some of those gaas fet with 6R on resistance and very low capacitance to try.
Im using one of those nice 2-12ghz hemts for the oscillator transistor.
Colin =^.^=