GPS antenna structure and principle

　　GPS antenna structure and principle

　　1. Composition of GPS antenna

　　GPS antenna is mainly composed of two core components: receiving antenna and preamplifier. Its core function is to convert the electromagnetic wave energy of the radio signal transmitted by the satellite into current that can be used by the receiver electronic devices. Most built-in GPS antennas use right-hand polarized ceramic dielectrics. The specific components include passive antenna, low-noise signal module, cable and connector. The functions of each part are as follows:

　　Passive antenna: This is the core technology of GPS antenna. Its signal receiving ability depends largely on its own ingredients, which directly affects the antenna's capture and reception of satellite signals.

　　Low-noise signal module (LNA): Mainly responsible for amplifying and filtering the received signal. The selection of components of this module is crucial. If it is not selected properly, it may increase the reflection loss of GPS antenna signal, and also cause excessive noise, affecting signal quality.

　　Cable: The selection should be based on reducing signal reflection as the standard, and impedance matching should be ensured to reduce signal loss during transmission.

　　Connector: Used to connect cables with other devices to ensure the stability and reliability of signal transmission.

　　2. Working Principle of GPS Antenna

　　The working process of GPS antenna involves the synergy of multiple key parts. The specific principles are as follows:

　　Ceramic sheet: The quality of ceramic powder and sintering process directly determine its performance. High-quality ceramic sheet and exquisite sintering process can make the ceramic sheet better sense satellite signals and lay the foundation for subsequent signal processing.

　　Silver layer: The silver layer covering the surface of the ceramic antenna will affect the resonant frequency of the GPS antenna. By reasonably designing the shape and area of the silver layer, the resonant frequency of the antenna can be matched with the satellite signal frequency to improve the signal reception efficiency.

　　Feed point: The passive antenna collects the resonant signal through the feed point and sends it to the back end. Due to the need for antenna impedance matching, the feed point is usually not in the center of the antenna, but is slightly adjusted in the XY direction. This impedance matching method is simple and does not increase the cost.

　　Amplifier: Its performance is related to the shape and area of the PCB carrying the passive antenna. Due to the ground bounce characteristic of the GPS antenna connector receiving signal, the selection of the amplifier gain must be coordinated with the back-end LNA gain to ensure that the signal can be stably transmitted after amplification to avoid signal distortion or attenuation.