Modeling, design and demonstration of multi-die embedded WLAN RF front-end module with ultra-miniaturized and high-performance passives

Abstract

This paper demonstrates, for the first time, a Wireless Local Area Network (WLAN) radio frequency (RF) front end module (FEM), incorporating the smallest, high-performance band-pass filter (BPF) on a 110μm-thin organic substrate with chip-last embedded actives and thin-film passives. The FEM consists of a power amplifier (PA) die, a switch die, and two low-noise amplifier (LNA) dies, integrated with a BPF and a low-pass filter (LPF). Full-wave electromagnetic (EM) simulations are employed to study the signal path loss, EM radiation and coupling. The BPF and LPF have 0.25dB and 0.5dB insertion loss respectively, with in-substrate dimensions of 1mm x 1mm x 0.05mm. The PA die shows a gain of around 10.8 dB at 2.4GHz. The path between the antenna and the amplifiers is also characterized to have a loss of 3dB. The electromagnetic coupling from the PA output to the LNA input and to the PA power supply is simulated using full wave EM solver HFSS and found to be higher than 60dB, indicating very good EM isolation. Each block of the FEM is individually characterized and combined using Agilent ADS to obtain the complete S-parameter performance. Both the transmitter and receiver chains have gain of 9dB.