Classification of GPS antennas

　　Classification of GPS antennas

　　The core function of GPS antennas is to convert electromagnetic waves emitted by satellites into electric currents. Since GPS signals are circularly polarized waves, all GPS antennas work in circular polarization. According to different classification standards, GPS antennas can be divided into the following categories:

　　1. Classification by polarization mode

　　GPS antennas are divided into vertically polarized antennas and circularly polarized antennas.

　　From the technical performance point of view, the effect of vertical polarization is inferior to circular polarization. Therefore, except for special application scenarios, GPS antennas generally use circular polarization; linear polarization is used under specific needs, but the application range is relatively narrow.

　　2. Classification by placement mode

　　It can be divided into GPS built-in antennas and GPS external antennas. The assembly position of the two has a significant impact on performance:

　　External antenna: Early GPS handheld devices mostly use external antennas that are basically isolated from the inside of the whole device, and electromagnetic interference (EMI) has little effect on it, and the satellite reception effect is excellent. For vehicle-mounted scenarios, the car shell (especially the explosion-proof film) will seriously hinder the GPS signal. At this time, the external antenna with a magnet can effectively solve this problem and become an important choice for vehicle-mounted GPS.

　　Built-in antenna: With the trend of miniaturization of equipment, built-in antennas are becoming more and more widely used. However, the built-in antenna needs to be installed above all metal devices, the shell must be electroplated and well grounded, and it must be away from EMI interference sources such as CPU, SDRAM, SD card, crystal oscillator, DC/DC, etc. to ensure the quality of signal reception.

　　3. Classification by power supply method

　　It is divided into active antenna and passive antenna.

　　Active antenna has a built-in low noise amplifier (LNA) and requires external power supply to enhance the signal. It is suitable for environments with weak signals; passive antenna does not require power supply and has a relatively simple structure. It is suitable for scenarios with strong signals and cost sensitivity.

　　Different types of GPS antennas are suitable for different application scenarios. When choosing, it is necessary to consider factors such as polarization requirements, installation space, and signal environment.