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.