The function of the GPS antenna is to convert the electromagnetic wave energy of the radio signal from the satellite into a current that can be picked up by the receiver electronics. The size and shape of the GPS antenna are very important, because these characteristics determine the ability of the antenna to acquire weak GPS signals.
According to needs, the antenna can be designed to work on a single L1 frequency, or on two frequencies, L1 and L2. Since GPS signals are circularly polarized waves, GPS antennas all work in circular polarization. Despite various constraints, there are still many different antenna types, such as monopole, dipole, spiral, four-arm spiral, and microstrip antennas.
1. Flat panel antenna
Flat panel antennas have become the most commonly used type of antenna due to their durability and relative ease of fabrication. Its shape can be round, square or rectangular, just like a copper-clad printed circuit board. It is composed of one or more metal sheets, so the most commonly used shape for GPS antennas is a blocky knot. Since the antenna can be made small, GNSS antenna types is suitable for aviation applications and personal handheld applications.
2. Four-arm helical antenna
The four-arm helical antenna is composed of four specifically curved metal lines. No grounding is required. It has the characteristics of a Zapper antenna as well as a vertical antenna. This ingenious structure enables the GPS antenna to have a gain of 3dB in any direction, increasing the time for satellite signal reception.