Influence of RF heating on microwave loss

Typically dielectric materials are used as a substrate for the fabrication of thin films. Some of the commonly used substrates are Quartz, Sapphire, MgO, LAO. Even though they are expensive the loss associated with these materials at high frequencies is low. In this paper the influence of RF heating on the high frequency loss of a commonly available OHP transparency film is scrutinized. It has been observed that the loss tangent of the material decreases once the 'OHP transparency film' is exposed to high RF power. The loss tangent decrease by 39% when the sample is exposed to RF power of 25 W for 30 minutes. The sample is also tested using microwave heating and conventional heating