Dual-Band Vertically Stacked Laminated Waveguide Filter Design in LTCC Technology

A new design method of dual-band filters with laminated waveguide (or substrate integrated waveguide) is proposed by taking advantage of the existence of multiple cavity modes. The major design concept is adequately choosing geometric shape of laminated waveguide resonators to control the frequency bands, and positions of open slots and feeding probes to realize the desired coupling coefficients and external quality factors at both bands simultaneously. Two design examples with third-order and quasi-elliptic filter responses are given and verified by experiments. By using the low-temperature co-fired ceramic technology, the laminated waveguide resonators are vertically stacked, and the filter size can be miniaturized.