H350 LGA Serials Module Hardware User Manual Page 35 of 37
7
RF Interface
7.1
Operation Frequency Band
7.1.1
Main Antenna
Operating Band
Tx
Rx
UMTS 2100 (Band I IMT)
1920–1980 MHz
2110–2170 MHz
UMTS 900 (Band II GSM)
880–915 MHz
925–960 MHz
GSM 900
880–915 MHz
925–960 MHz
DCS 1800
1710–1785 MHz
1805–1880 MHz
7.2
RF PCB Design
7.2.1
Layout Guideline
As H350 does not have a RF connector, so for RF line, microstrip line is recommended. The shorter the better,
insert loss is less than 0.2dB; impedance is less than 50ohm.
It is recommended to mount H350 module and antenna connector to the same side of layout.
Add a π-type circuit (two parallel device ground pin directly to the main land) for antenna matching.
Figure 7-1π-type Circuit
7.2.2
Impedance
The RF lines
impedance
should not exceed 50 ohm.
7.3
Antenna Design
7.3.1
Main Antenna Design Requirements
(1) Antenna Efficiency
Antenna efficiency is the ratio between antenna input power and radiation power. The radiation power of an
antenna is always lower than the input power due to the following factors: return loss, material loss, and
