A design of vertical coupled stacked bandpass filter using multilayer structure without via

This paper presents a new symmetric multilayer coupling configuration in order to reduce the size of microwave bandpass filter. To verify this approach, simulation and experimental investigation were made. A four sections bandpass filter was design and implemented. Both simulation and experimental performances of the filter are presented and with a good agreement. By using symmetric signal trace and ground designs accomplish the vertical coupling in multilayer system. Apply this technology in filter design can achieve the vertical extension in multilayer structure instead of the horizontal extension. Any order filter can be made in a limited footprint.