User's Manual

Smart Machine Smart Decision
SIM7100A_User Manual_V1.01 2014-12-11
58
4.2 Antenna Design Guide
SIM7100A provides RF antenna interface. Customer’s antenna should be located in the host board and
connected to module’s antenna pad through micro-strip line or other types of RF trace and the trace
impedance must be controlled in 50Ω. The maximum gain of the LTE B2/WCDMA B2 antenna gain
should not exceed 3.4dBi,
LTE B4 antenna gain should not exceed 1.9 dBi, LTE B5/WCDMA B5 antenna
gain should not exceed 2.8 dBi,
LTE B17 antenna gain should not exceed 1dBi considering the SAR radio.
SIMCom recommends that the total insertion loss between the antenna pad and antenna should meet the
following requirements. No antenna gain may be used that would exceed the 2W EIRP power limit in
1900MHz band.The input impendence of the antenna should be 50Ω, and the VSWR should be less than 2.
● WCDMA 2100/1900<0.9dB
● WCDMA 900/850<0.5 dB
● LTE (F<1GHz) <0.5dB
● LTE (1GHz<F<2GHz) <0.9dB
● LTE (2GHz<F) <1.2dB
To facilitate the antenna tuning and certification test, a RF connector and an antenna matching circuit
should be added. The following figure is the recommended circuit.
Figure 33: Antenna matching circuit (MAIN_ANT)
In this figure, the components R4,C3,C4 and R4 is used for antenna matching, the value of components
can only be got after the antenna tuning, usually, they are provided by antenna vendor. By default, the R3,
R4 are 0 Ohm resistors, and the C3, C4 are reserved for tuning.
The RF test connector in the figure is used for the conducted RF performance test, and should be placed as
close as to the module’s antenna pin. The traces impedance between components must be controlled in
50ohm.