The electromagnetic wave emitted by the satellite is converted into electric current. Since the GPS signal is a circularly polarized wave, all antennas work in a circularly polarized manner. GPS antennas are divided into internal and external antennas according to their location. The internal antennas are divided into passive antennas and active antennas.
1. In terms of polarization, GPS antennas are divided into vertical polarization and circular polarization.
With current technology, the effect of vertical polarization is not as good as circular polarization. Therefore, except for special circumstances, GPS antennas will use circular polarization and linear polarization.
2. In terms of placement, it is divided into GPS internal antenna and GPS external antenna.
The assembly location of the antenna is also very important. Early GPS handsets mostly used flipped antennas. At this time, the antenna is basically isolated from the inside of the whole device, and EMI hardly affects it, and the satellite reception effect is very good. With the trend of miniaturization, GPS antennas adopted are internal antennas.
At this time, the GPS antenna must be above all metal components, and the inside of the shell must be electroplated and well grounded, and away from EMI interference sources, such as CPU, SDRAM, SD card, crystal oscillator, DC/DC. The application of car GPS will become more and more common. The car shell, especially the car anti-explosive film, will seriously hinder the GPS signal. An external antenna with magnet is very necessary for car GPS.
3. GPS antennas are divided into active and passive in terms of power supply.