Design of LNA using body biasing techniques for enhanced reliabilty and robustness

Nowadays, miniaturization of transistors has led to issues such as process variability, aging effects and field variations. These effects deteriorate the performance of RF circuits, and are found to be more pronounced in Low Noise Amplifier (LNA) affecting the gain and noise figure. In this work, a cascode LNA is designed with adaptive body biasing technique at 11.4 GHz with the objective of reducing variations in the gain and noise figure. In order to make the circuit low power, self-adaptive body biasing is designed which utilizes the DC voltage available in the cascode configuration. Moreover, in an attempt to measure the robustness of the proposed design field variation parameters such as drain induced barrier lowering (DIBL) and process transonductance, βhave been demonstrated. Using small signal analysis, it is found that the body transconductance, gmb, reduces the variations in LNA. Results show that gain and noise figure variations have been reduced by 33.8% and 32.7% respectively for adaptive body biasing and in case of self-adaptive body biasing; the respective variations are reduced by 22.6% and 20.2%. Similarly, the DIBL coefficient has been improved by 20% and the β variations are found to be less for body biased LNAs. The proposed circuits were designed and simulated in 65 nm Cadence SpectreRF.