Design of a Novel Harmonic-Suppressed Microstrip Low-Pass Filter

A novel harmonic-suppressed microstrip low-pass filter (LPF) is proposed which is composed of defected ground structures and stepped-impedance shunt stubs as series $L$ and shunt $C$ components in the pass-band. Due to the attenuation poles of two kinds of resonators, it is found that harmonic responses are not only suppressed effectively, but the rejection in the stop-band is also deep and wide. Besides, the proposed LPF can be compactly implemented since both kinds of resonators have slow-wave characteristics.