Abstract
The purpose of this research is to develop applications of thin-film L-C band-pass filters. We made 3-step L-C band-pass filters that consist of thin-film inductors and thin-film capacitors, determined the L-C constitution and characteristics of the filters, and investigated the Q value of each L and C by simulation. The filters thus produced are small (3.4×2.8×0.6 mm3 = 0.006 cm3), even when the substrate is included, and are applied in the frequency range of about 400 MHz. Their characteristics showed a low insertion loss of -9 dB at 400 MHz, and the wide band characteristics of 75 MHz were obtained for a bandwidth of -3 dB. A Q value of about 20 was obtained for a resonance tank circuit composed of thin-film L-C, and a Q value of 20-50 was obtained for a bridge capacitor containing thin-film capacitors. The values of L, C, and Q for the thin-film inductor, thin-film capacitor, and stray capacitor of the circuit were investigated by simulating the measured results.
