Help with the phase shifter/tuner.

[ccarrot]

Hi,

I'm going to design a phase shifter (or called phase tuner) with 0-90 degree tuning range. It works between 100MHz-200MHz, i.e. the input signals are two quadrature digital inputs with f=100-200 MHz.

I checked a lot of references, but they usually works at RF band. I tried a current-steering topology (as shown below), but i'm not able to make it work I think it is because 100-200 MHz is very low.

Is anybody can help me out?
(1) Will current-steering topology work at 100-200MHz?

(2) Any circuit advised?


Thank you!

 

[jiripolivka]

You can try a fast opamp connected as a phase shifter and use a varicap to vary the phase. For 100-200 MHz, depending on signal power, you can use a Lecher wire (twin lead, two parallel wires) with a sliding contact, to set the phase delay. You will have to use also a power splitter, to generate the reference and the delayed signal.