Vertically Integrated Microwave-Filters Using Functional Via Structures in LTCC

A novel approach to filter design including proof of concept is demonstrated through the first-time vertical integration of Chebyshev lowpass- and bandpass-filters in low temperature cofired ceramic (LTCC) multilayered substrates. Integration is achieved by replacing planar stub elements by resonant vertical interconnect accesses (vias) which serve the functional purpose of a vertical transmission line and therefor add another full degree of freedom in circuit design. The filters shown are comprised of two lowpass filters of 3rd- and 5th-order, and one bandpass filter of 5th-order. The general description of the design is given together with full filter specifications. Full-wave simulations based on the finite element method (FEM) and measurement results are compared to each other and are in excellent agreement.

Subjects

bandpass filter

low temperature cofired ceramics

lowpass filter

multilayered substrate

vertical integration

vias

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Vertically Integrated Microwave-Filters Using Functional Via Structures in LTCC