引用: kiifwerw 发表于 2019-3-5 07:57
由于我们使用网络分析仪估计天线的调谐频率，因此辐射电阻和抗损耗的概念是否与在不同频率下显示的多次下降有关。
此外，为了交叉检查，我们可以去测量S11和S21参数。
对于调谐频率，我们应该观察到该频率的下降（在S11的情况下），而我们应该观察该频率的峰值（对于S21）。
> {quote：title = saviour2009写道：} {quote}>辐射电阻和抗损耗的概念是否与在不同频率下显示的多次下降有关，因为我们使用网络分析仪估计调谐频率
天线
>>此外，为了交叉检查，我们可以去测量S11和S21参数。
对于调谐频率，我们应该观察到该频率的下降（在S11的情况下），而我们应该观察该频率的峰值（对于S21）。
您需要定义要测量的内容。
如果有人对我说天线被调谐到F的频率，那么我认为它们意味着它在F处产生共振。这就是定义意味着输入阻抗纯粹是真实的。
那可能是也可能不是| S11 |的地方
骤降。
它经常在一个设计合理的天线中。
测量天线的合理测量位置，必须考虑电缆长度的影响，因为这会改变相位。
因此，更容易在电缆末端进行校准，并将其拧到天线上。
您要测量S21的唯一方法是使用另一个测试天线。
在这一点上出现了一系列全新的并发症。
同样，您需要定义要测量的内容。
对于BOTH天线，输入阻抗，自由空间路径损耗，辐射方向图，增益和实现的增益都会随频率而变化。
我怀疑你对你想测量的东西有点困惑。
您能否向我们提供有关天线的更多详细信息，以及您想要做什么？
请注意，8753系列上的长电缆存在问题，如果使用长电缆（这对于天线测量非常常见），则需要将扫描速度降低到低于仪器自动设置的速度。
戴夫。
以上来自于谷歌翻译
以下为原文
> {quote:title=saviour2009 wrote:}{quote}
> Whether the concepts of radiative resistance and loss resistance have got anything to do with the multiple dips being shown at different frequencies, since we are using a network analyzer to estimate the tuning frequency of the antenna.
>
> Moreover, in order to cross check can we go for measuring both S11 and S21 parameters. For a tuning frequency, we should observe a dip (in case of S11) at that frequency whereas we should observe a peak (for S21) at that frequency.
You need to define what you want to measure. If someone said to me an antenna was tuned to a frequency of F, then I would think they mean it resonates at F. That be definition means the input impedance is purely real. That may or may not be where the |S11| dips. It quite often is in a reasonably well designed antenna. Measuring where the antenna is reasonate measure you must take into account the effect of the cable length, as that will alter the phase. Hence it is easier to calibrate on the end of the cable, and screw that to the antenna.
The only way you are going to measure S21 is to use another test antenna. At which point a whole new set of complications arrise. Again, you would need to define what you what to measure. Input impedance, free space path loss, radiation pattern, gain and realized gain would all vary with frequency for BOTH antennas.
I suspect you are a bit confused about what you want to measure. Can you give us more details about the antenna, and precisely what you want to do?
Be aware there's an issue with long cables on the 8753 series, and that if you use long cables, which is quite common for antenna measurements, you need to slow the sweep speed down below that which is automatically set by the intrument.
Dave.
引用: kiifwerw 发表于 2019-3-5 07:57
由于我们使用网络分析仪估计天线的调谐频率，因此辐射电阻和抗损耗的概念是否与在不同频率下显示的多次下降有关。
此外，为了交叉检查，我们可以去测量S11和S21参数。
对于调谐频率，我们应该观察到该频率的下降（在S11的情况下），而我们应该观察该频率的峰值（对于S21）。
> {quote：title = saviour2009写道：} {quote}>辐射电阻和抗损耗的概念是否与在不同频率下显示的多次下降有关，因为我们使用网络分析仪估计调谐频率
天线
>>此外，为了交叉检查，我们可以去测量S11和S21参数。
对于调谐频率，我们应该观察到该频率的下降（在S11的情况下），而我们应该观察该频率的峰值（对于S21）。
您需要定义要测量的内容。
如果有人对我说天线被调谐到F的频率，那么我认为它们意味着它在F处产生共振。这就是定义意味着输入阻抗纯粹是真实的。
那可能是也可能不是| S11 |的地方
骤降。
它经常在一个设计合理的天线中。
测量天线的合理测量位置，必须考虑电缆长度的影响，因为这会改变相位。
因此，更容易在电缆末端进行校准，并将其拧到天线上。
您要测量S21的唯一方法是使用另一个测试天线。
在这一点上出现了一系列全新的并发症。
同样，您需要定义要测量的内容。
对于BOTH天线，输入阻抗，自由空间路径损耗，辐射方向图，增益和实现的增益都会随频率而变化。
我怀疑你对你想测量的东西有点困惑。
您能否向我们提供有关天线的更多详细信息，以及您想要做什么？
请注意，8753系列上的长电缆存在问题，如果使用长电缆（这对于天线测量非常常见），则需要将扫描速度降低到低于仪器自动设置的速度。
戴夫。
以上来自于谷歌翻译
以下为原文
> {quote:title=saviour2009 wrote:}{quote}
> Whether the concepts of radiative resistance and loss resistance have got anything to do with the multiple dips being shown at different frequencies, since we are using a network analyzer to estimate the tuning frequency of the antenna.
>
> Moreover, in order to cross check can we go for measuring both S11 and S21 parameters. For a tuning frequency, we should observe a dip (in case of S11) at that frequency whereas we should observe a peak (for S21) at that frequency.
You need to define what you want to measure. If someone said to me an antenna was tuned to a frequency of F, then I would think they mean it resonates at F. That be definition means the input impedance is purely real. That may or may not be where the |S11| dips. It quite often is in a reasonably well designed antenna. Measuring where the antenna is reasonate measure you must take into account the effect of the cable length, as that will alter the phase. Hence it is easier to calibrate on the end of the cable, and screw that to the antenna.
The only way you are going to measure S21 is to use another test antenna. At which point a whole new set of complications arrise. Again, you would need to define what you what to measure. Input impedance, free space path loss, radiation pattern, gain and realized gain would all vary with frequency for BOTH antennas.
I suspect you are a bit confused about what you want to measure. Can you give us more details about the antenna, and precisely what you want to do?
Be aware there's an issue with long cables on the 8753 series, and that if you use long cables, which is quite common for antenna measurements, you need to slow the sweep speed down below that which is automatically set by the intrument.
Dave.
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