Multi-source Intermodulation in a Loaded-line Phase Shifter

This paper reports on multi-source intermodulation (IM) in a tunable loaded-line true-time delay phase shifter. It is demonstrated that IM products in the distributed structure sum up constructively or destructively to form IM maxima or minima. In particular, it is demonstrated that backward IM products can be minimized with an odd number of unit cells. The reported results are useful both for understanding how to minimize backward IM in a phased-array antenna system and to understand distributed passive intermodulation (PIM) in guided wave structures.