A Low-Pass Filter Using Lumped Elements

Application ID: 15675

Passive devices can be designed using lumped element features if both the operating frequency of the device and the insertion loss of lumped elements are low. This example simulates two types of lumped element filters that are similar to lumped ports, except that they are strictly passive and there are predefined choices for inductances and capacitance.

First, a five-element maximally flat low-pass filter is built to compute frequency responses that show the cutoff at the intended frequency. The geometry of each element (surface-mount device, SMD) is simplified as a 2D boundary and the electrical performance is modeled using the Lumped Element boundary condition in the Electromagnetic Waves, Frequency Domain interface. Then, a band-pass filter transformed from the low-pass filter design is simulated in the same frequency range. Both filter models present the S-parameters and electric field distribution.

This model example illustrates applications of this type that would nominally be built using the following products: