I need to shift the phase of a signal in the 2 GHz range. However, the problem is that this phase shift needs to be trimmable. It must be adjusted only once. Unfortunately it is very difficult to properly simulate the necessary phase shift in advance, and there may also be some manufacturing tolerances.
I wonder whether there is a way of making an adjustable phase shifter, for instance with a trimmer cap? The phase shift should be adjustable in a range of, say, 90°. Further, of course the phase shifter must be matched to 50 ohms.
I thought a RC network may do the job, but unfortunately it is not matched at its ports and further has a lowpass or highpass characteristic, which I would like to avoid.
Best Answer
I doubt you could use a trimmer cap in that frequency range. At those frequencies everything becomes extremely sensitive to parasitics and probably you would need specialized microwave circuitry.
Anyway you could do with a module like this. Excerpt from the app note:
I just googled for digitally controlled microwave phase shifters. If the digital control through USB seems overkill, maybe you could find some pre-built module with a more "low-level" interface (e.g. SPI, I2C).