Compact Lumped-Element LTCC Bandpass Filter for Low-Loss VHF-Band Applications

A compact multilayer lumped-element bandpass filter which employs a novel third-order schematic for the low-loss wide passband along with high selectivity is proposed in this letter. The filter characteristics are analyzed mathematically and graphically when the practical implementations of the filter get discussed in detail afterward. A prototype filter of extremely small size 0.004 lambda(g)x0.004 lambda(g)x0.0003 lambda(g) is realized in a ten-layer low-temperature co-fired ceramic substrate. Experimental results demonstrate that the proposed filter achieves a wide fractional bandwidth of 62% with remarkably low insertion loss, which shows great potentials for miniaturized high-resolution very-high-frequency communications applications.