LNA Design Principles

Here follows a basic tutorial on LNA design described by example using ADS.

The steps involved usually follow the sequence:

  • Define LNA requirements

  • Select device(s)

  • Find good bias operating point and design DC bias circuit

  • Optimise source match for noise figure, input return loss and stability

  • Find load match for good return loss – conjugate match, sometimes IP3 / P1dB as well

  • Create impedances with distributed matching – eg microstrip

  • Check linear performance (S11, S21, S12, S22, GD, phase_linearity, NF)

  • Check non-linear performance (use actual modulation if needed) (OIP3, OIP2, EVM)

  • MTBF and environmental performance testing

  • Design for manufacture (yield analysis, low cost BOM, pcb design rules)