The design of novel multilayer slow-wave aperture-coupled microstrip bandpass filters

New multilayer aperture-coupling microstrip slow-upave bandpass filters using an open-loop, resonator loaded with interdigital capacitive fingers is proposed. The new filter configuration consists of two arrays of microstrip open-loop resonators loaded with four fingers and eight fingers that can be coupled through the apertures on the common ground plane. The filter is not only compact in size, but also exhibits spurious stopband rejection. Filters of this type with elliptic function and Chebyshev response are demonstrated. There is good agreement between the measured and simulated results. (c) 2006 Wiley Periodicals. Inc.