AD8340's phase control

Question I have a question about AD8340's phase control with Vibb and Vqbb. I tried it, but the output phase seems not to change following my settings. Could you please help explain its working mode? Answer The phase formula just expressed the phase variation, it is not absolute phase. For example, if Vi=0.5V, Vq=0V, then the output signal will stay at the original phase, it means no phase modification. If Vi=0V, Vq=0.5V, then the output signal phase will increase 90 degree.

AD8340, AD8341, and ADL5390 Vector Modulators: IBBP, IBBM, QBBP, and QBBM Input Impedance to Ground

Q. What is the input impedance to ground for the I and Q inputs of the AD8340, AD8341 and ADL5390 vector Modulators? A. These inputs connect to the bases of transistors. So the input impedance will be high and will consist of a resistive and capacitive component. Simulations show an impedance of about 23 megaohms in parallel with approximately 400 fF of capacitance from each input to ground. Attachments: https://ez.analog.com/cfs-file/__key/communityserver-wikis-components-files/00-00-00-01-12/AD8340_5F00_zin.emf

What is the Group Delay of the AD8340 and AD8341? How does is change over gain?

For both parts the group delay does not change appreciably with gain and there is less than 1ns of delay over each part’s frequency range. Below are Group Delay VNA screen captures of the AD8340 and AD8341, respectively.