Lumped Element Filter Design And Optimization

Three benchmark filter circuits are introduced in this article that demonstrate how the Modelithics CLR Library™ can predict performance precisely, improving design flow efficiency.

The three filter circuits are:

1. 2.2 GHz low-pass
2. 900 MHz high-pass
3. 5.4 GHz band-pass

The filters were designed, fabricated and measured. Excellent agreement was obtained between measurement of the final product and simulations using Modelithics CLR Library models. The CLR Library consists of Global Models™ whose format and advantages are well described in a separate application note1. This note discusses the design process, each simulation and optimization step, and measured and simulated results for each filter. The design methods followed for these filters, which all demonstrate "close-the-loop" measurement and simulation results in one pass, can easily be emulated for filter, matching, and bias network design in your environment.

The availability of complete hardware and simulation kits for these filters allows interested designers the opportunity to thoroughly understand how the simulations are set up, and to make their own measurements of the filter circuits presented.