Characterisation and application of embedded lumped elements in multilayer advanced thick-film multichip-module technology

This study presents the characterisation and modelling of embedded multilayer and miniaturised lumped element inductors and capacitors in thin-film microstrip (TFMS) configuration with remarkably high performance using cost-effective photoimageable thick film multichip-module (MCM) technology. The proposed miniaturised multi-turn spiral inductors are designed with circular geometry and removal of the ground plane underneath the coil structure to improve the self-resonance frequency (SRF) as well as the quality factor (Q). The circular 2.5 turn spiral inductor has inductance of 3.7 nH, a high SRF of 8.4 GHz, high-quality factor and measures only 0.6 x 0.7 mm(2). Using the high-performance lumped elements, a fully embedded TFMS low-pass filter (LPF) is demonstrated with a remarkably low-passband insertion loss of 0.3 dB, return loss better than 25 dB, wide spurious free stop band attenuation >45 dB and yet highly miniaturised, measuring only 5.4 x 1.1 x 0.3 mm(3). The measured response characteristics are in excellent agreement with the predicted response. The miniaturised filter is highly suitable for use as a discrete component or as part of the intermediate frequency (IF) section of a compact integrated microwave or millimetre-wave MCM. This represents one of the highest passive component performances ever reported for ceramic-based MCM technology.