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GT-1612-MTBD
GPS&Beidou Receiver Module
www.gotop-zzu.com
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Revision: V2.0.1-January 2015
3.2. External Active Antenna
The following figure is a typical reference design with active antenna. In this mode, DC on the VCC_RF pin is
powered by VCC and supplies power to the external active antenna.
Figure 14:
Reference Design for Active Antenna
C1, C2, L1 is used for power supply and filtering effect to the external active antenna, RF_IN antenna to a circuit
part (BOLD line) for high frequency microstrip line, PCB in the design of this part of the line to calculate the
characteristic impedance of the high-frequency line according to the principle of high frequency wiring.
Requirements: this section of the line in the 1575.42MHz frequency characteristic impedance requirement is 50
ohm.
Table 8: Recommended Active Antenna Specification
In order to ensure the short protection function can work effectively, please select a DC-open (DC-impedance
between the SMA's inner signal needle and outside ground) GPS&Beidou active antenna. You can measure the
DC-impedance with a common and simple multimeter on few samples, and the value is generally in M ohm
level.
Antenna Type
Specification
Active Antenna
Center frequency: 1575.42MHz
Band width: >5MHZ
VSWR: <2 (Typ.)
Polarization: RHCP or Linear
Noise figure: <1.5dB
Gain (antenna): >-2dBi
Gain ( embedded LNA): 20dB (Typ.)
Total gain: >18dBi(Typ.)