Test systems for characterizing devices under test (DUTs) are provided. A test system for testing a DUT in a shunt configuration may include a signal generator and a matching network that is coupled between the signal generator and the DUT and that is optimized to apply desired voltage/current stress to the DUT with reduced source power. The matching network may be configured to provide matching and desired stress levels at two or more frequency bands. In another suitable embodiment, a test system for testing a DUT in a series configuration may include a signal generator, an input matching network coupled between the DUT and a first terminal of the DUT, and an output matching network coupled between the DUT and a second terminal of the DUT. The input and output matching network may be optimized to apply desired voltage/current stress to the DUT with reduced source power.