Owing to the high-frequency and high-power requirements for communication integrated circuits (ICs) in today's rapid development of electronic technology, the intensity of electromagnetic field from the ICs can be significant. This article shows a failure due to this enhanced electromagnetic field in a gallium nitride based high electron mobility transistor high-frequency power amplifier. Inputs were provided as per the rated values and failures are observed on the drain and gate terminals. Detail failure analysis on the failed samples, using focus ion beam technique for cross sectioning the damaged area and examining under scanning electron microscopy/ energy dispersive X-ray spectroscopy, reveals the meltdown of the materials at the drain and gate terminals. Electromagnetic simulations and measurements are performed, and the failure mechanism is confirmed to be due to the magnetic field induced eddy current in the drain metal plate of the transistor, on top of the designed operating current in the metal plate.