Ka-Band LNA Design Using Systematic Circuit Design Methodology and Design Applicable Equations

This paper presents a systematic methodology, using design applicable equations aided Ka-band Low Noise Amplifier (LNA) design. The LNA design is based on cascode amplifier topology with common-emitter configuration using 0.12$-\mu$m Silicon Germanium (Si-Ge) hetero-junction bipolar transistor (HBT) technology. The designed LNA exhibited a gain S21 greater than 20 dB across the Ka-band frequency range. A noise Figure of less than 3 dB is obtained over the Ka-band. The input reflection coefficient S11 and output reflection coefficient are below -10dB, and the reverse isolation S12 is below −10dB. The systematic methodology is presented as a sectioning of the LNA design into parts that contribute to the performance. Then, by optimizing of the building parts, and the connection between them, we achieve a highly performing LNA. Applicable theory equations are used to optimize performance parameters and synthesize inductors layout. The LNA design provides sufficient gain, low noise Figure and lower circuit complexity. To our knowledge, these are state-of-art results and show validity of the design technique.