The gain of an antenna is a passive phenomenon - power is not added by the antenna, but simply redistributed to provide more radiated power in a certain direction than would be transmitted by an isotropic antenna.
所以，天线是无源器件，不会平白无故地把信号放大，只是做一个信号的整形而已。至于我为什么会把dBi当作是一个放大的单位，那是因为在视距传播公式里会有
Secondly, we examine the COBRA with segmented parabolic reflectors. The design of the reflector is re-expatiated, which is composed of several equivalent parts of parabolic reflector with the same axis and focus. The radiation formulas are deduced with Current Distribution Methods, and the radiation patterns are calculated. The results show that it can produce high-gain circularly polarized field in the boresight direction (the gain is about 30dBi when the diameter of the reflector is 1.3m) and its 3dB bandwidth is 78%. The radiation formulas of TEM coaxial mode as the radiation mode of COBRA are also deduced. At last, a new folding antenna has been put forward and designed.
在COBRA天线方面：重新阐述了反射面的设计公式，该反射面是几块不同焦距抛物反射面的共焦共轴组合；用电流分布法推导了天线的辐射公式并编写了计算程序，利用该程序对天线的辐射方向图和频带宽度进行了讨论，计算表明这种天线可以在轴线上获得高增益的圆极化波(当反射面直径为1.3m时增益为30dBi)，其3dB带宽为78％；推导了同轴TEM模作为COBRA天线馈源时的辐射公式；最后，提出并设计了一种折叠式COBRA天线。
KWGR614 modelling is beautiful, fashionable, use two dismountable 2dbi antenna, make signal stronger.
KWGR614造型美观、时尚，采用两根可拆卸2dbi天线，使信号更强。
Overall, the patterns are omnidirectional and suitable for practical use. Themeasured gain was 0.4 dBi at 948 MHz, 1.7 dBi at 1790 MHz, and 1.1 dBiat 2465 MHz.
所衡量的增益在全球行动通讯系统频带的 948 MHz 处是 0.4 dBi ，在集散控制系统频带的 1790 MHz 处是 1.7 dBi，而在工业科学与医疗系统频带的 2465 MHz 处是 1.1 dBi。
But now with the emergence of standard 5dBi products, greatly enhancing the coverage of product stability and connectivity.
不过现在有了标配5dBi的产品出现，大大增强了产品的覆盖范围以及连接稳定性。
The easiest way to see Class::DBI in action is to build a simple application with it.
最容易了解Class：：DBI的方法就是用它来建立一个例子程序。
Sometimes the information we store in the database can be used to work with non-Class::DBI modules.
有时我们需要在数据库里存储其他模块需要使用的数据。
The reference case is a 3-sector system with antenna gain of 18 dBi.
其参考方案是具有18DB 天线增益的三扇形天线系统。
The rats were randomly divided into control group and DBI groups at 3, 6, 12, 24 and 72h, and on 7d.
采用自由落体撞击法制作成年雄性SD大鼠弥漫性脑损伤模型，大鼠随机分为对照组、伤后3、6、12、24、72h和7d组。
Based on DBI method, an iteration algorithm is proposed for solving this kind of strongly non-linear problems.
在数值模拟运算时利用矩量法进行离散处理，并采用正则化原则避免求解病态矩阵方程。
4 DBi gain at 1593 MHz is also achieved.
同时，天线在1593MHz的增益达到9.4dBi。
Taurine can protect the DBI rats by down-regulating the expression of MMP-3 in brain tissue.
牛磺酸可通过下调弥漫性脑损伤大鼠脑皮层MMP-3的表达发挥对弥漫性脑损伤的保护作用。
It gives about 4 dB loss of gain of antenna in relation to theoretic value with an efficiency of 100%.
它损失了大约4dBi的天线增益，理论上说就是100%的效率。
They give about 4 dB loss of antenna gain in relation to the theoretic value with an efficiency of 100%.
它损失了大约4dBi的天线增益，理论上说就是100%的效率。
The Born iterative method is only suitable to weakly non-linear problems.
基于DBI方法(Distorted-Born Iterative 方法)，提出了一种求解弹性波强非线性逆散射问题的迭代方法。
The improved antenna can obtain polarization diversity signal and a higher gain (7.7dBi).
测试结果表明该天线在某些频段的增益可以达到7.7dBi。
Effects of the charge of DBI, temperature, time and pH value on increasing MOW deinking pulp brightness, decreasing dirt count during the course of DBI bleaching were studied first in this paper, and the best condition of DBI bleaching was set up.
本文首先研究DBI漂白混合办公废纸脱墨浆时NaHSO3和NaBH4的配比、漂白温度、时间以及pH值等对提高脱墨浆的白度和降低油墨尘埃度的影响，确定DBI漂白脱墨浆的最佳工艺条件，接着研究最佳工艺条件下的DBI和HB-1组合漂白，实验结果表明，先进行HB-1段漂，后进行DBI段漂，可以获得更好的漂白效果。
The results of 34% and 6% bandwidth, 7.9dBi and 9.98~12.15 dBi gain, F/B ratio 16dB and 10~12dB are simulated by IE3D for stacked aperture coupled MPA and MSBA, and the beam steered from –30 to +30 degrees at operating frequency.
在制程设计时则应用微机电制程的微型开关来改善电子式的开关在高频的缺点，并使天线阵列与微型开关皆使用微机电制程技术来完成。
Finally, this paper propose a feasible method to fabricate Ka-band stacked aperture coupled MPA and MSBA built on a permittivity εr = 11.9, tanδ=0.001 silicon wafer by micromachined techniques.
最后利用IE3D设计Ka频段的堆叠式开槽耦合微带天线与可控波束微带天线阵列，在模拟阻抗良好的匹配情况下，其频宽有34 %及6 %，天线增益为7.9 dBi与9.98~12.15 dBi，F/B比为16dB及10~12dB，而可控波束微带天线阵列的扫描角度为±30度。
Two types of 2×2 Aperture coupled microstrip steering beam antenna array composed by foregoing two type phase shifter are built on FR4 substrate for C band application. The measured antenna gain are 9.2 dBi and 8.8 dBi, whereas the front to back ratio is 7~9dB with the beam scan angle in E plane is ±31degrees and ±30 degrees. The measured bandwidth of two type aperture coupled MSBA is 1~2GHz.
其次将二种相移器与开槽耦合微带天线结合，设计成2× 2的开槽耦合可控波束微带天线阵列，当在天线阵元间馈入0度~180度的相位差时，结合相移器的两种天线阵列，波束可扫描角度在E面分别为±31度与±30度，F/B比在7~9dB之间，增益则为8.8 及 9.2 dBi，且均有1~2GHz的频宽。