Chapter 4 – Antennas and Cables
Multi-Tech Systems, Inc. MultiModem Wireless EDGE, GPRS, and CDMA Modems with GPS (S000376A)
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Chapter 4 – Antennas and Cables
The Antenna
The antenna sub-system and integration in the application is a major issue: Choice of antenna (type, length,
performances, thermal resistance, etc.) These elements could affect GSM performances such as sensitivity and
emitted power.
EDGE, GSM, and CDMA Antenna
The integrated modem antenna connector is a SMA connector.
The SMA connector incorporates a 'Screw-on' action
in order to make the connection easier while providing an excellent RF performance. An additional advantage is its
small physical size, which is 50% of the standard MCX connector.
This type of connector is suitable for the standard ranges of flexible and semi-rigid cables. The characteristic
impedance of the MMCX coaxial connector is 50 ohm. The antenna manufacturer must guarantee that the antenna
will be working according to the radio characteristics presented in the table below.
EDGE and GSM Radio Characteristics
GSM 850
E-GSM 900
GSM 1800
GSM 1900
Frequency RX
869 to 894 MHz
925 to 960 MHz
1805 to 1880 MHz
1930 to 1990 MHz
Frequency TX
824 to 849 MHz
880 to 915 MHz
1710 to 1785 MHz
1850 to 1910 MHz
RF Power Stand
2W at 12.5% duty cycle 2W at 12.5% duty cycle 1W at 12.5% duty cycle 1W at 12.5% duty cycle
Impedance
50 ohms
VSWR
<2
Typical Radiated Gain
0 dBi on azimuth plane
CDMA Radio Characteristics
CDMA 800
CDMA 1900
Frequency RX
869 to 894 MHz
1930 to 1990 MHz
Frequency TX
824 to 849 MHz
1850 to 1910 MHz
Impedance
50 ohms
VSWR
<2
Typical Radiated Gain
0 dBi in at least one direction
GSM / CDMA Antenna Example
An antenna that meets the requirements for use with this product is included with your purchase.
