> I am trying to implement a multiple antenna (16 channels) beamforming
> system with 2.6GHz carrier freq. To capture the phase difference between
> channels, I need to downconvert the 2.6GHz RF to complex baseband using
> some I/Q mixers. I found out (from Marki) that a 2.6GHz I/Q mixer costs
> over $150, which is way above my budget limit... I wonder if there is any
> trick to avoid having mulitple mixers for such case?
You need multiple baseband signals, as passband is simply too high speed
to deal with in any simple manner.
This means you must have however many mixers as you require baseband
signals, and each LO must be the same (or at least have some very well
defined phase offset from each other such that you can compensate for it
in the baseband processing).
You can surely find mixers for 2.4GHz cheaper than $150, is there
anything special about the mixer you need?