Analysis of Total Ionizing Dose Effect on a Linear RF Power Amplifier

Abstract

After accidents at nuclear power plants (NPPs), ensuring safety and reliability has become critically important. Monitoring NPPs is essential to detect and prevent accidents early. Wireless sensor networks (WSNs) are best suited for monitoring, but need to be robust against radiation to work effectively in harsh conditions. An important building block of a WSN node is the radio frequency (RF) power amplifier (PA), which should be able to provide the power to transmit the data even in the event of an accident. This article investigates the impact of total ionizing dose (TID) on the performance of a 2.4 GHz complementary metal-oxide-semiconductor (CMOS) RF PA. TID-induced changes in threshold voltage ( V-th( )) result in a displacement of the quiescent operating point (Q-point), leading to variations in critical performance metrics such as gain and efficiency. The PA is specifically designed to tolerate the increase in drain current caused by radiation, thereby maintaining functionality under radiation exposure. The PA is exposed to ionizing radiation at a dose rate of 200 Gy/h up to a total dose of 5 kGy using a Co-60 gamma source facility to evaluate its radiation tolerance and assess performance degradation. Measured results show a decline in small-signal gain ( S-21 ) and a reduction in power-added efficiency (PAE) from 12.2% to 9.6% as the total dose increases, with a sharp degradation observed beyond 1 kGy.