A compact lumped-element lowpass filter using low temperature cofired ceramic technology

The design method for a small lowpass filter (LPF) having a multilayer structure, which can be embedded in RF modules, is presented. Low loss, three dimensional inductors and capacitors have been investigated and incorporated to design a chip-type LPF. The Chebyshev LPF has been designed with a cutoff frequency of 2 GHz, a ripple of 0.1 dB, and a high attenuation (<−30 dB). The low temperature cofired ceramic (LTCC) materials have a dielectric constant of 7.8, a loss tangent of 0.0015, and a metallization of silver. The characteristics of the embedded passives (of which the structures were rectangular helical inductors and parallel-plate capacitors) have been analyzed by 3D structure simulator and the equivalent circuit simulated.