Structure and principle of GPS antenna

1、 Composition of GPS antenna

GPS antenna is composed of receiving antenna and preamplifier. The function of GPS antenna is to convert the electromagnetic wave energy of the radio signal from the satellite into the current that can be absorbed by the electronic device of the receiver. Most of the built-in GPS antennas are right-handed polarized ceramic media, and their components are: passive antenna, low-noise signal module, cable and connector.

1. Passive antenna is the core technology of GPS antenna. The signal receiving ability of a GPS antenna mostly depends on the composition of its passive antenna.

2. Low noise signal module, also known as LNA, is the part that amplifies and filters the signal. The selection of components is also very important, otherwise it will increase the reflection loss of GPS antenna signal and cause excessive noise.

3. The selection of cables should also take reducing reflection as the standard to ensure the matching of impedance.

2、 Working principle of GPS antenna

Ceramic sheet: the quality of ceramic powder and sintering process directly affect its performance.

Silver layer: the silver layer on the surface of ceramic antenna can affect the resonance frequency of GPS antenna.

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

Amplifier: the shape and area of PCB carrying passive antenna. Because the received signal of GPS antenna connector has the characteristics of ground bounce, the selection of amplifier gain must match the back-end LNA gain.