What is a pi-network?

A pi-network (π-network) is a type of electronic filter or impedance matching network named for its structural resemblance to the Greek letter pi (π). It is composed of three reactive components: one series component placed between two parallel (shunt) components that connect to ground. In typical radio frequency applications, this means the network consists of either one series inductor and two shunt capacitors (forming a low-pass filter) or two shunt inductors and one series capacitor (forming a high-pass filter). Other options are incorrect because "power incidence" is a fictitious term in this context, and a pi-network specifically uses exactly three reactive components, not four. Furthermore, it relies on a ground connection for its shunt components, meaning it is never isolated from ground.