PHEMT-Based Ultrawideband Low Noise Amplifier with Room-Cryogenic Temperature Operability

An ultra wideband MMIC low noise amplifier (LNA) based on the 0.15-μm pHEMT 3MI Triquint power process has been demonstrated. A feedforward noise cancellation technique was employed to reduce the thermal noise in the LNA. The LNA has a surface area of 2 mm by 2 mm. The gain of LNA is 15 dB between 400 MHz and 12.5 GHz with ±0.3dB gain flatness across the band. The return loss at both input and output is better than -10 dB. The measured noise figure at 300 K varied between 1.5 dB at 400 MHz and 2.6 dB at 12 GHz, and the MMIC´s DC power consumption is less than 200 mW. The LNA was further characterized at cryogenic temperatures in terms of gain, input/output return loss and noise figure. The noise figure measured at 100 K dropped to 1.1 dB at 12 GHz. The gain improved at cryogenic temperatures, the overall variation in the gain between 300 K and 100 K is less than 2 dB while the input and output return losses did not change significantly. This wideband LNA can be used in applications requiring low noise and/or low temperatures.