Pao-Nan Lee; Yu-Chang Hsieh; Hung-Lun Lo; Chang-Ho Li; Fan-Hsiu Huang; James Lin; Wei-Chu Hsu; Chen-Chao Wang
5G communication has been widely implemented since 2020, especially in the FR1 sub-6GHz range. Bands n77, n78, and n79 are critical because of their higher frequencies and wider bandwidth, which also creates new filter-design challenges.
In this work, we propose a new structure combining OSAT fan-out RDL inductors and foundry MIM capacitors to enhance filter performance. An 800 MHz low-pass-filter test vehicle indicates the structure can sustain at least 38 dBm, compared with 36 dBm in a conventional integrated passive device.
Band-pass filters for bands n77 and n79 were designed and fabricated with the new structure. Insertion loss was about 1.44 dB for band n77 and 2.07 dB for band n79. Maximum sustainable input power was 34 dBm for both filters.
Besides single filters, fan-out RDL can replace conventional coreless packaging substrates to realize a thinner RF front-end module.
Published in: 2022 IEEE 72nd Electronic Components and Technology Conference (ECTC)
