What's wrong with my RF shifter?

I have design a RF shifter which is working around 2.4GHz, the IC is HMC631, only to find that it only have a phase range about 45deg, what's wrong with it ? My Shifter's I&Q range is 0.5v - 2.5v. I have design a similar one using AD8341, but i without any trouble. Who can help?

In its simplest operation, you get the greatest phase difference as you get the closest to the capacitor or inductor. That way you have 90 degrees between V and A.

At this frequency, outputs 1 and 2 are about 45 degrees leading and trailing the incoming signal. The net difference between the two outputs is about 90 degrees.

This does not mean that I know anything about your setup and how to achieve what you want.

Thank you. HMC631 is a Vector Modulator, so the way it works different from analog phase shifters. My setup is quite simply, but i doesn't work.

What's the reason? Everything that can go wrong with the device or circuit....

the first things I would check:
1) is the I or Q input short circuited with a solder blob
2) did you blow up the I or Q input with too much current (you should be using series current limiting resistors until you know how the circuit works)
3) the big ground slug under the package is not grounded
4) you have not DC blocked the rf output port
5) you are not differentially driving the input
6) the DC level of the differential inputs is wrong