Professor Katehi is an expert in the areas of development and characterization (theoretical and experimental) of microwave, millime­ter printed circuits; the computer-aided design of VLSI interconnects; the development and characterization of micro-machined circuits for microwave, millimeter-wave and sub-­millimeter-wave applications including MEMS switches, high-Q evanescent mode filters and MEMS devices for circuit re-configurability; the development of low-loss lines for sub-millimeter-wave and terahertz frequency applications; theoretical and experimental study of unipla­nar circuits for hybrid-monolithic and monolithic oscillator, amplifier and mixer applica­tions; theoretical and experimental characterization of photonic band-gap materials.