Quarter-wave transformers are used to match a load impedance with a transmission line in order to minimize reflections.
In this example, a 350 Ohm is matched to a 100 Ohm microstrip line. The load is represented by a 2D RLC lumped element. The bandwidth is also analyzed
Find the example here: https://kb.lumerical.com/en/index.html?pic_passive_quarter-wave-transformer.html