LTCC Evanescent-Mode Filter

Figure 1: Filter structure designed for LTCC and based on inductive and capacitive posts

Figure 2: HFSS simulated frequency response


Multi-layer LTCC structure based on through & blind vias. Operates as a waveguide post filter with cavities reduced by capacitive loading. Interconnects to asymmetric 50W strip-line by end probes.

Design Method

Design method is based on solving of electromagnetic scattering problem of junctions of double ridged waveguide. Semi-numerical solution is derived for several types of junctions loaded with iris elements. The obtained formulation is represented as fortran code and compiled into design tool. The design tool consists of four program modules; filter synthesizer, frequency response simulator, and optimizer and HFSS/AutoCAD converter. Accuracy of software is within manufacturing and tuning margins.