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What is a Dual-feed Antenna?
社会保险有哪些
Dual Feed Patch Architecture
Dual feed antennas are two orthogonally oriented dipoles. When the received signals of each dipole are summed, after a 90 degree pha shift of one of the signals, it perfectly replicates the circular respon over the full bandwidth of the antenna. This greatly improves rejection of cross polarized (multi-path) signals and thus provides much higher precision than single feed antennas.
A single feed patch antenna is circular only at its single frequency of resonance. As carriers 70道寺院素菜谱
depart from this single frequency of resonance, they will appear increasingly more elliptical to this antenna. So when a single feed antenna is ud to access two constellations, such as GPS (at 1575.42 MHz) and GLONASS (at 1602 MHz), it is tuned to the mid-point of the two frequencies; typically 1590 MHz. The result is the GPS and the GLONASS signals appear elliptical to this antenna. So when the single feed antenna receives the GPS and the GLONASS signals, it also receives cross-polarized (multi-path) signals which are also elliptical. The end result is statistically very poor precision.
关于读书的四字词语简单的网名Figure 2 illustrates this point well. At the tuned frequency of 1590 MHz, the single feed antenna has a cross polarized signal rejection of about 25 dB but only about 5 dB of rejection at the frequencies of interest; 1575.42 MHz and 1602 MHz.
GNSS receivers are at the mercy of the quality of the signal prented by the antenna. No receiver can fully mitigate the effects of a poor antenna.鞍山美食
Figure 2 – Respon of a Single Feed Antenna versus Respon of an Accutenna™ antenna
Figure 2 provides an excellent illustration of the effects of using Accutenna® technology which provides a circular respon over the entire bandwidth. The cross polarization rejection at the two frequencies of interest is significantly better: approximately 25 dB at
1575.42 MHz and 20 dB at 1602 MHz.
什么是双馈天线？
双饲料补丁架构
双饲料补丁架构
双馈天线是两个正交导向的双极。当每个偶极子的接收信号被总结时，在一个信号的90度相位偏移之后，它完美地复制了整个天线的全带宽的循环响应。这大大提高了对交叉极化（多路径）信号的排斥，因此比单馈天线的精度高得多。
单馈线天线只有在单一频率的共振时才会循环。当载波离开这个单一频率的共振时，它们将会越来越多地出现在这个天线上。因此，当一个单馈天线用于访问两个星座时，例如GPS（1575.42 MHz）和GLONASS（1602 MHz），它被调到两个频率的中间点;通常1590 MHz。结果是GPS和GLONASS信号在这个天线上显得椭圆。因此，当单馈天线接收到GPS和GLONASS信号时，它也接收到交叉极化（多路径）信号，这些信号也是椭圆的。最终结果在统计上非常不准确。
投标报价书
图2说明了这一点。在1590 MHz的调谐频率下，单馈天线有一个交叉极化信号被拒绝约25分贝，但在感兴趣的频率上只有大约5分贝的拒绝;1575.42 MHz和1602 MHz。
GNSS接收器受天线所显示的信号质量的影响。没有一个接收器能够完全减轻天线差的影响。
图2-单个馈电天线的响应与Accutenna天线的响应
图2——单馈天线的响应与Accutenna天线的响应
功能键盘图2提供了一个很好的例子，说明了使用Accutenna技术的效果，它提供了对整个带宽的循环响应。在这两种频率上的交叉极化拒绝明显更好：大约在1575.42 MHz和1602 MHz的20 dB。
