Application62 Designing a Low-Pass Filter with Lumped-Constant Boundary Condition

An electromagnetic solver of Femtet assists you to design electronic components like resistor, inductor, and capacitor utilizing lumped-constant boundary condition.

The specifications of the low-pass filter and the circuit are as shown in Fig. 1.
The lumped constant is set on the microstrip line as shown in Fig. 2. The inductor elements are in series with the signal line and the capacitor elements are used as shunts on the reverse side of the substrate.
Fig. 3 shows the setting of the lumped constant as a boundary condition. Resistor, inductor, and capacitor can be defined inn parallel. S-parameter can be defined as well.
As the result in Fig. 4 shows, the characteristics specified in Fig. 1 are obtained.

Fig. 1: Specifications of Low-Pass Filter and Equivalent Circuit

Fig. 2: Analysis Model

Fig. 3: Boundary Condition Setup

Fig. 4: Result