Loss in tunable microstrip lines

Electromagnetic energy loss in the micro-mechanically tunable microstrip line is studied including dielectric loss in substrate´s medium and ohmic loss in metal electrodes. When total loss in the device is relatively small, loss mechanisms contribute additively, so complex effective permittivity can be used to account both phenomena. This simplifies analysis and design of tunable microstrip lines. It is shown that with micro-mechanical tuning both dielectric and metal loss decrease comparing to those of conventional line.