Active GPS antenna module example

In active Global Positioning System (GPS) modules, Low-Noise Amplifier (LNA) supply input is typically combined with RF output. Therefore, a DC decoupling capacitor (C2) in the RF line and an RF choke inductor (L1) in the supply line are required. Using a capacitor (C1) with an RF choke inductor for RF grounding is recommended.

Additional supply filtering capacitors may be used to suppress noise in the supply. It is recommended to minimize current consumption by providing GPS module supply only when the GPS is active, for example by switching supply on and off by COEX0 signal. Load switch is a simple solution for this purpose.

An example of the implementation is shown in GPS implementation with active GPS module.

Figure 1. GPS implementation with active GPS module

Table 1. Components of GPS implementation with active GPS module
Reference	Description
L1	RF choke inductor, 68 nH
C1	RF grounding capacitor, 56 pF
C2	DC block capacitor, 56 pF
SW1	Load switch
P1	Connector for active GPS module

Note: As the active GPS antenna module includes an antenna, the position of the active GPS antenna module in the device is critical. Guidance for the placement of the GPS antenna module provided in the GPS antenna module datasheet must be followed.

Some active GPS modules have outputs for external matching components that can be used to tune the antenna. Examples of active GPS modules are listed in the following table.

Table 2. Examples of active GPS modules
Vendor	Product	Description
Antenova	M20057-1 SMD Active Global Navigation Satellite System (GNSS) Antenna	SMT
Taoglas	AP.17F.07.0064A 17mm Two Stage GPS/Galileo Active Patch Antenna Module	I-PEX