Examples > Microwave Circuits > 1GHz Low Noise Amplifier
Print version of this topic
2GHz BJT Low Noise Amplifier12 GHz Microstrip Filter

Design of a 1GHz Low Noise Amplifier

Location: \examples\MW_Ckts\LNA_1GHz_prj

Objective

This example shows how to examine stability, noise and gain, and how to design the input and output matching networks for a 1GHz LNA. It also compares the simulation data with those from layout.

Setup

  1. "ModelVerif.dsn" shows how to compare two sets of data: the device model and measured S-parameters for the device are simulated to validate the model.

  2. "BiasSetup.dsn" determines the required VBE so that the operating point of the model matches that of the S-parameter-based component.

  3. "Bias_Network.dsn" performs an optimization to calculate the required bias network resistors for the device.

  4. "SparamsNoise.dsn" shows how to set up the S-parameter simulation control to calculate noise parameters for the device and how to generate constant noise figure circles.

  5. "Stability.dsn" calculates and displays input and output stability circles for the device and also shows the effect of adding a stabilizing networks on the output.

  6. "Match1.dsn" and "Match2.dsn" calculate the required input match network for minimum noise figure at 1GHz.

  7. "Match3.dsn" and "Match4.dsn" calculate the required output matching network for the device with the optimum input noise match network in place.

  8. "FinishedAmp.dsn" calculates gain, input and output match, and noise figure for the completed amplifier.

  9. "AmpLayout.dsn" is a subcircuit containing the layout and schematic of the finished amplifier, replacing ideal components with models from the SMT Passive Component Library.

  10. "SimFromLayout.dsn" contains the symbol for AmpLayout and simulation controllers. Results are compared to the ideal results from FinishedAmp.dsn.

1GHz Low noise amplifier schematic

Analysis

S22 and S11 ideal versus simulation from layout

Figure 1: S22 and S11: ideal versus simulation from layout.

Amplifier gain comparison ideal simulation and layout

Figure 2: Amplifier gain comparison between ideal simulation and that from layout.

Noise figure comparison

Figure 3: Noise figure comparison.

Amplifier layout

Figure 4: Amplifier layout.

Notes

  • Some design files in this example use a transistor from the "Packaged BJT Library". "AmpLayout.dsn" also uses SMT passive components. You can edit these files and view results but in order to simulate, you must have a license for the Packaged BJT Library and the SMT Passive Components Library.