Which type of network provides the greatest harmonic suppression?

Among the common impedance matching networks (L, Pi, and Pi-L), the Pi-L network provides the greatest harmonic suppression. It essentially cascades a Pi-network with an L-network, increasing the number of reactive components acting as a low-pass filter. This increased complexity creates a steeper roll-off curve above the operating frequency. As a result, high-frequency harmonics generated by nonlinearities in the amplifier are heavily attenuated before they can be transmitted. Standard L-networks and Pi-networks have fewer filter poles, meaning they do not block harmonics as aggressively as the Pi-L design.