Bandpass filter of serial configuration with two finite transmission zeros using LTCC technology

This study proposes a second-order bandpass filter of serial configuration. The filter schema incorporates a grounding capacitor, connecting the two conventional parallel LC resonators with the ground, to provide two finite transmission zeros. The impedance matrix and graphical solutions describe proposed filter´s operation principle. To demonstrate the proposed filter schema, two bandpass filters, with center frequencies of 2.44 and 4.8 GHz, were designed and implemented using low-temperature co-fired ceramic multilayer technology. The measured results were found to agree well with the simulation results. The 2.44-GHz fabricated bandpass filter was found to possess low in-band insertion loss and high out-band suppression, making it suitable in wireless local area networks, Bluetooth, and RF home links.