Huawei ME909u-521 Hardware Manual page 45

HUAWEI ME909u-521 LTE LGA Module
Hardware Guide
Figure 3-22 Complete structure of the stripline
Figure 3-23 Routing for the RF interface
Please use impedance simulation tool to calculate RF MAIN pad impedance. The RF
MAIN pad dimension of ME909u-521 is 1.1 mm (L) x 0.9 mm (W). You can get the
impedance with lower than 50 Ω calculated by the impedance simulation tool. Since
the target impedance is 50 Ω for RF trace, the recommended solution is that to carve
out the copper area of the second layer that projected by the RF MAIN pad at top
layer. How many layers should be carved out depend on the PCB permittivity, track
width, and distance from the floor of your own PCB. Our target is to make the RF
MAIN pad impedance as closer to 50 Ω as possible.
Issue 05 (2017-12-15)
Huawei Proprietary and Confidential
Copyright © Huawei Technologies Co., Ltd.
Description of the Application Interfaces
45