Fully Embedded 2.4GHz Compact Band Pass Filter into Multi-Layered Organic Packaging Substrate
In this paper, fully embedded 2.4GHz WLAN band pass filter (BPF) was investigated into a multi-layered organic packaging substrate using high Q spiral stacked inductors and high Dk MIM capacitors for low cost RF System on Package (SOP) applications. The proposed 2.4GHz WLAN BPF was designed by modifying chebyshev second order filter circuit topology. It was comprised of two parallel LC resonators for obtaining two transmission zeros. It was designed by using 2D circuit and 3D EM simulators for finding out optimal geometries and verifying their applicability. It exhibited an insertion loss of max -1.7dB and return loss of min -l7dB. The two transmission zeros were observed at 1.85 and 6.7GHz, respectively. In the low frequency band of 1.8GHz∼1.9GHz1.8GHz∼1.9GHz, the stop band suppression of min -23dB was achieved. In the high frequency band of 4.1GHz∼5.4GHz4.1GHz∼5.4GHz, the stop band suppression of min -l8dB was obtained. It was the first embedded and the smallest one of the filters formed into the organic packaging substrate. It has a size of 2.2×1.8×0.77mm32.2×1.8×0.77mm3.