Knowles DLI - Knowles DLI is a global supplier of microwave and millimeter wave components for optical and wireless communications, military, medical, semiconductor, aerospace, and transportation markets. DLI is a manufacturer of high-q multi-layer capacitors (MLC) and single-layer capacitors (SLC), resonators, filters, broadband DC blocks, thin film components, and custom ceramic components. In 2004, DLI acquired Voltronics Corporation, a world leader in precision variable capacitors.