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GPS antenna and 3G antenna manufacture
Sep 27, 2017

GPS antenna classification

⒈ from the polarization method GPS antenna is divided into vertical polarization and circular polarization. With today's skills, the role of vertical polarization than circular polarization. So in addition to special circumstances, GPS antenna will use circular polarization.

⒉ from the placement method GPS antenna is divided into built-in antenna and external antenna. Antenna installation orientation is also very important. Early GPS handheld multi-use eccentric antenna, at the moment the antenna and the whole internal isolation, EMI is not its impact on the formation of excellent role. Now with the miniaturization of the trend, GPS antenna and more use built-in. At this point the antenna is necessary in all metal equipment above the shell to be plated and well grounded, away from EMI interference sources, such as CPU, SDRAM, SD card, crystal, DC / DC. WIFI antenna

Car GPS application will be more and more. While the car's shell, especially the car explosion-proof film will be a serious GPS signal to stop. An external antenna with a magnet (which can be attached to the roof) is very necessary for car GPS. GPS antenna structure is now the vast majority of GPS antenna for the right-handed polarized ceramic media, and its composition are: ceramic antenna, low noise signal module, cable, connector during which ceramic antenna is also called passive antenna, dielectric antenna, PATCH, it GPS antenna is the core skills of the location. A GPS antenna signal capacity, most depending on what ingredients with its ceramic ingredients.

The low-noise signal module, also known as the LNA, is part of the signal that is expanded and filtered. Its meta-equipment selection is also very important, or will increase the GPS signal reflection loss, and the formation of noise is too large. The selection of the cable should also be reduced as a standard to ensure that the impedance of the match. 4G antenna

GPS antenna function of the impact of GPS antenna function is the first few aspects

1, ceramic pieces: ceramic powder is good or bad and sintering technology directly affect its function. The ceramic tile used in the market is mainly 25 × 25, 18 × 18, 15 × 15, 12 × 12. The larger the ceramic area, the greater the dielectric constant, the higher the resonant frequency, the better the bear. Most of the ceramic pieces are square plan, in order to ensure that the resonance in the XY direction is fundamentally common, and then achieve the role of uniform convergence.

2, silver layer: ceramic antenna appearance Silver layer can affect the antenna resonance frequency. Aspiring GPS ceramic chip frequency exactly falls on 1575.42MHz, but the antenna frequency is very simple to be affected by the surrounding environment, especially in the machine, it is necessary to adjust the appearance of silver coating to adjust the frequency from scratch 1575.42MHz. So the GPS machine manufacturers in the acquisition of the antenna must be cooperation antenna manufacturers, supply the machine sample for testing.

3, feed point: ceramic antenna through the feedback point to collect resonance signals and sent to the back-end. Because the antenna impedance matching factor, the feed point is usually not in the center of the antenna, but in the XY direction to do small adjustments. This impedance matching method is simple and does not add cost. Only the movement in the uniaxial direction is called a single biased antenna, both of which are called two biases.

4, to expand the circuit: carrying ceramic antenna PCB shape and area. Because GPS has a touch of the characteristics of the rebound, when the scenery is 7cm × 7cm without interruption of the earth, patch antenna performance can play to the extreme. Although subject to the appearance of structural constraints, but try to adhere to the appropriate area and shape uniform. Expanding the selection of the circuit gain is necessary to cooperate with the backend LNA gain. Sirf GSC3F request signal input before the total gain shall not exceed 29dB, otherwise the signal over-saturation will occur self-excited.

GPS antenna has four primary parameters: Gain, VSWR, Noise figure, Axial Ratio. During which a special emphasis on axle ratio, it is a measure of the machine is not the same direction of the signal gain difference between the primary indicators. Because the satellites are randomly distributed in the hemisphere sky, so to ensure that the antenna in all directions are near the sensitivity is very important. Axis than the antenna function, the appearance of the structure, the whole circuit and EMI and other effects.