A compact semi-lumped lowpass filter with three lumped capacitors is presented in this paper. With this design, three transmission zeros can be obtained within the stopband to enhance its bandwidth. Furthermore, a transmission zero located near the passband is used to achieve sharp selectivity. A meander line between source and load is also introduced to get a compact size. Therefore, the proposed filter has a sharp skirt and wide stopband in comparison with traditional low-pass filters. A microstrip lowpass filter with lumped capacitors is designed and fabricated with the standard single-layered printed circuit board (PCB) technology. The measured S-parameters of the proposed filter agree well with the simulated ones, and the filter achieves the design performance.
展开▼
