The microstrip filter with multiple stacked capacitively-loaded coupled lines

In this paper, multiple stacked capacitively-loaded coupled lines are adopted for the design of microstrip filter. The filter shows different stopband behavior with respect to even or odd total number of resonators. The transmission zeros may be located around the lower, higher, or both sides of the passband´s skirt. Moreover, the use of capacitively- loaded lines can produce another transmission zero in the higher stopband. Adopting these characteristics, the bandpass filter and diplexer can be developed readily. These experimental results are evident in our proposed structure.