Dynamic control of propagating electromagnetic waves using tailored Millimeter plasmas on microstrip structures

Millimeter plasmas were tailored to play a role as dynamic devices of microwave components, that is, to control electromagnetic wave propagation dynamically on a microstrip line. The generation of millimeter plasmas with their relatively long discharge channel (∼3 mm) was in high-pressure (20-200 torr) Ne, and they were successfully arranged near and on the conductor of microstrip lines. When such a plasma was set perpendicularly to the conductor to form a T junction, a significant reduction of electromagnetic wave transmission along the metal conductor was observed. The reduction rate depended on the discharge current and the number of T junctions. These experimental results are compared with the case of 2 MHz launching for crude electron density measurements and the numerical results of propagating electric fields in a two-dimensional model.