beam-steering - Question and answers

I'm working on a Ku-band phased array antenna with 64 elements for a small satellite project. The antenna uses a corporate feed network and phase shifters for beam steering. In simulations (using CST Microwave Studio), I'm getting beam pointing errors of up to 2 degrees off the target direction, which is unacceptable for my link budget. I've calibrated the phase shifters and adjusted the element spacing, but the errors persist. Any advice on tuning or alternative approaches would be appreciated.