I had interviews over the phone before I started my internship. 3 people interviewed me and mostly they asked me about circuit desing concepts, but the questions were mostly about the basics. Each one took about 45 min to 1 hour. The people who interviewed me were mostly from TX and EM groups. People should expect questions from LNA design summary, signal generation circuits/oscillators, oscillator phase nosie, mixers, maybe some PLL, and similar stuff related to RX systems. Also, some RX system level signal/noise questions can be asked.