Novelminiaturized low-pass filtersfrom artificial transmission line structures

A novel design on miniaturized low-pass filters from artificial transmission line structures is proposed. Reactance components, i.e. capacitors and inductors, are directly constructed from microstrip structures based on electromagnetic simulation and parameter extraction. The constructed reactance components are integrated to build low-pass filters. The results of a fifth-order Butterworth, 0.25, 0.5, and 1 dB ripple Chebyshev filters, which are realized by the proposed method, are presented. The proposed low-pass filters are compact and their sizes are about 20% of conventional microstrip low-pass filters. The simulation agrees well with the measurements, which shows the validation of the proposed design method. The miniaturized low-pass filters may be applied to many microwave systems.