sales@motor-techtop.com
- 作者:
- 來源:
- 日期 : 2020-07-03
Specializing in the production of GPS vehicle antenna, GPS built-in antenna / ceramic antenna .GPSantenna performance is mainly the following aspects:
1, ceramic: ceramic powder and sintering quality directly affect its performance. Ceramic plate is 25 x 25,18 x 18, 15 x 15,
12 x 12. Ceramic chip area is larger, the dielectric constant is bigger, its resonance frequency is higher, the better the effect of acceptance. Ceramic pieces are mostly square design, in order to
Guarantee in the XY direction resonance are basically the same, so as to achieve uniform collect stareffect.
In 2, a layer of silver: ceramic antenna surface silver layer can influence the antenna resonance frequency.The ideal GPS ceramic chip frequency point accurately fall in 1575.42MHz, but the antenna frequency
Very susceptible to the effect on the environment, especially in the assembly, must by adjusting the silver surface coating profile, to modulate the frequency to maintain in 1575.42MHz.
3, feed point: ceramic antenna through a feed point collection resonance signal and sent to the rear.Because the antenna impedance matching causes, generally not in the antenna feed point
Is central, but in the XY direction to do fine adjustment. The impedance matching method is simple and nocost increase. Only in the single axis direction is known as a single partial
Antenna, in two axes are mobiles called double deflection.
4, amplifying circuit: bearing ceramic antenna PCB shape and size. Because GPS has a reboundcharacteristics, when the background is 7cm ×7cm without interruption of the earth,
The patch antenna performance can play to the extreme. Although the appearance of the structure and other factors, but try to keep a considerable area and uniform shape. Amplifier gain
The selection must be back-end LNA gain. Sirf GSC3F request signal input prior to the total gain of not more than 29dB, otherwise the signal saturation will produce self-excited.
The GPS antenna have four important parameters: gain ( Gain ), wave ( VSWR ), noise coefficient (NoiseFigure ), axial ratio ( Axial ratio ).
With particular emphasis on the axial ratio, which is a measure of the different direction signal gaindifference index. Because the satellite is randomly distributed in the hemisphere sky,
So to ensure that the antenna on each direction all have similar sensitivity is very important. Axial ratio by the antenna performance, appearance and structure, the internal circuit and EMI effects.
