Introduce The GPS Antenna in Detail
GPS antenna refers to the antenna for positioning or navigation by receiving satellite signals. This antenna is used to convert electromagnetic waves emitted by satellites into electric current. Because the GPS signal is circularly polarized, all antennas are circularly polarized.
GPS antenna is divided into built-in antenna and external antenna according to location.
The built-in antenna can be divided into passive antenna and active antenna. The passive antenna is mainly ceramic medium, and the ceramic antenna mainly presents square design, and its resonance frequency will increase with the increase of GPS ceramic antenna area; The active antenna is mainly composed of ceramic antenna, LNA (low noise signal module), cable, connector and a sealed waterproof ring. So, what is the difference between active and passive GPS in addition to the design mechanism?
Compared with GPS passive antenna, GPS active antenna adds more signal amplifiers to improve sensitivity and signal-to-noise ratio; In addition, different active antennas have different requirements for the range of feed voltage, so the appropriate feed voltage should be selecte according to the parameters of the antenna.
GPS passive antenna receives satellite signals through ceramics, with poor anti electromagnetic interference; When in use, there is no need for feeding, but feeding does not affect the use; Impedance matching is required when using GPS passive antenna, because the general passive antenna is not the standard 50 ohm impedance. If it is not matched, the received signal will be weak and the receiver may not be able to locate.
Compared with the passive antenna, the active antenna with high gain and strong anti-interference ability is superior. However, if there is an LNA module in the chip, the passive antenna should be selecte. On the contrary, the active antenna should be used. In short, the key to choose active antenna or passive antenna is whether the antenna input pin of the chip can feed.
What are the common connectors of GPS antenna in the antenna? The built-in ceramic antenna of GPS normally uses rf1.13 wire + IPEX terminal; GPS external antenna: RG174 wire + SMA connector or RG174 wire + fakra connector.
There are several factors affecting the performance of GPS antenna: first, the area of GPS ceramic antenna. At present, GPS ceramic antenna mainly includes 25 * 25 * 4mm, 18 * 18 * 2mm, 15 * 15 * 4mm and 12 * 12 * 4mm. Generally, the larger the area of ceramic sheet, the greater the dielectric constant, so that the higher the resonance frequency of the antenna, the better the grounding effect; Second, the silver layer on the surface of the ceramic antenna affects the resonant frequency of the antenna. In order to ensure that the frequency point of the antenna is not affected by the surrounding environment and is stably maintained at the ideal GPS frequency feed point of 1575.42MHz, the surface coating shape needs to be adjusted to achieve; The third is the feed point, which is used by the antenna to collect the resonance signal and send it to the back end; Finally, the amplification circuit of GPS antenna. The selection of amplification circuit gain must match the back-end LNA gain.
With the continuous R & D, design and manufacturing of GPS antenna, at present, GPS double-layer superimposed ceramic antenna has begun to enter the market. Zhongruicheng is also increasing its investment in R & D. It is forging ahead with the idea of becoming a well-known professional, innovative and influential antenna design, manufacturing and solution provider in China.