I had a phone interview, which was 20 test question about some topics like link budget. I passed it. Then had a phone interview with the hiring manager, then they sent a problem which would be sent only if the position like this is for PhD. It took one week for me to respond, which impressed them. Then I had an on site interview which was a presentation of my work and a panel interview where they asked many technical and behavioral questions. Although the steps were tough the group was very friendly.