Determining Electromagnetic Energy Loss Through a Radio-Frequency Transmission Line by Infrared Thermal Imaging

This paper presents a technique for measuring local electromagnetic energy loss through a transmission line by infrared thermal imaging. The technique offers an attractive route to investigate solid-state radio-frequency (RF) structures with different sizes and an arbitrary layout of lines by achieving an electromagnetic energy mapping over a wide frequency range between 300 MHz and 6 GHz. The measurement setup and the microstrip RF transmission line test device are described. An analytical model expressing the dissipated power profile as a function of signal frequency, transmission line features, and impedance mismatch is presented. Electromagnetic loss and temperature increase induced by dissipation are numerically studied. Experimental results are presented and discussed.