A high temperature wideband low noise amplifier for downhole applications

As the oil industry continues to drill deeper to reach new wells, electronics are required to operate at extreme pressures and temperatures. Coupled with substantial real-time data targets, the need for robust high speed electronics is quickly on the rise. This paper presents a high temperature wideband low noise amplifier (LNA) with zero temperature coefficient maximum available gain (ZTCMAG) biasing for a downhole communication system. The proposed LNA is designed and prototyped using 0.25 μm GaN on SiC RF transistor technology, which is chosen due to the high junction temperature capability. Measurements show that the proposed LNA can operate reliably up to an ambient temperature of 230 C with a minimum noise figure (NF) of 2.0 dB, average gain of 16.1 dB, and input P1dB of 4.0 dBm from 230.5–285.5 MHz. The maximum variation with temperature from 25°C to 230°C is 1.53 dB for NF and 0.65 dB for gain.