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The impact of GPS antenna performance is mainly the following aspects
May 10, 2017

1, ceramic antenna: ceramic powder is good or bad and sintering process directly affect its performance. The ceramic tile used in the market is mainly 25 × 25, 18 × 18, 15 × 15, 12 × 12. The larger the ceramic antenna sheet area, the greater the dielectric constant, the higher the resonant frequency, the better the acceptance. Ceramic pieces are mostly square design, is to ensure that the resonance in the XY direction is basically the same, so as to achieve the effect of uniform convergence.

 

2, silver layer: ceramic antenna surface silver layer can affect the antenna resonance frequency. The ideal GPS ceramic chip frequency accurately falls at 1575.42MHz, but the antenna frequency is very susceptible to the surrounding environment, especially in the machine, must be adjusted by adjusting the appearance of the silver coating to adjust the frequency to maintain at 1575.42MHz The So the GPS machine manufacturers in the purchase of the antenna must be with the antenna manufacturers to provide the whole sample for testing.

 

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

 

4, amplification circuit: carrying ceramic antenna PCB shape and area. As the GPS antenna has a touch to the characteristics of the rebound, when the background is 175px × 175px without interruption of the earth, patch antenna performance can play to the extreme. Although subject to the appearance of structural constraints, but try to maintain a considerable area and shape uniform. The gain of the amplifier circuit must be selected in conjunction with the back-end LNA gain. Sirf GSC3F requires that the total gain before signal input should not exceed 29dB, otherwise the signal over-saturation will produce self-excited.