FCC E9B - 天线与传输线系统

#E9B01🔗

What is the 3 dB beamwidth of the antenna radiation pattern shown in Figure E9-1?

图 E9-1 所示天线辐射图的 3 dB 波束宽度是多少？

75 degrees

75度

50 degrees

50度

✓ 正确答案

25 degrees

25度

30 degrees

30度

#E9B02🔗

What is the front-to-back ratio of the antenna radiation pattern shown in Figure E9-1?

图 E9-1所示天线辐射方向图的前后比是多少？

36 dB

36分贝

14 dB

14分贝

24 dB

24分贝

18 dB

18分贝

✓ 正确答案

#E9B03🔗

What is the front-to-side ratio of the antenna radiation pattern shown in Figure E9-1?

图 E9-1 所示天线辐射方向图的前侧比是多少？

12 dB

12分贝

24 dB

24分贝

18 dB

18分贝

14 dB

14分贝

✓ 正确答案

#E9B04🔗

What is the front-to-back ratio of the radiation pattern shown in Figure E9-2?

图 E9-2 所示辐射方向图的前后比是多少？

15 dB

15分贝

28 dB

28分贝

✓ 正确答案

3 dB

3分贝

38 dB

38分贝

#E9B05🔗

What type of antenna pattern is shown in Figure E9-2?

图 E9-2 所示的天线方向图是什么类型？

Elevation

海拔

✓ 正确答案

Azimuth

方位角

Near field

近场

Polarization

偏振

#E9B06🔗

What is the elevation angle of peak response in the antenna radiation pattern shown in Figure E9-2?

图 E9-2 所示天线辐射方向图中峰值响应的仰角是多少？

45 degrees

45度

75 degrees

75度

7 . 5 degrees

7. 5度

✓ 正确答案

25 degrees

25度

#E9B07🔗

What is the difference in radiated power between a lossless antenna with gain and an isotropic radiator driven by the same power?

具有增益的无损天线和相同功率驱动的各向同性辐射器之间的辐射功率有什么区别？

The power radiated from the directional antenna is increased by the gain of the antenna

定向天线辐射的功率因天线增益而增加

The power radiated from the directional antenna is stronger by its front-to-back ratio

定向天线辐射的功率因其前后比而更强

They are the same

他们是一样的

✓ 正确答案

The power radiated from the isotropic radiator is 2.15 dB greater than that from the directional antenna

各向同性辐射体的辐射功率比定向天线的辐射功率大2.15 dB

#E9B08🔗

What is the far field of an antenna?

什么是天线的远场？

The region of the ionosphere where radiated power is not refracted

电离层中辐射功率不被折射的区域

The region where radiated power dissipates over a specified time period

在指定时间段内辐射功率耗散的区域

The region where radiated field strengths are constant

辐射场强恒定的区域

The region where the shape of the radiation pattern no longer varies with distance

辐射方向图形状不再随距离变化的区域

✓ 正确答案

#E9B09🔗

What type of analysis is commonly used for modeling antennas?

什么类型的分析通常用于天线建模？

Graphical analysis

图形分析

Method of Moments

矩量法

✓ 正确答案

Mutual impedance analysis

互阻抗分析

Calculus differentiation with respect to physical properties

关于物理性质的微积分微分

#E9B10🔗

What is the principle of a Method of Moments analysis?

矩量法分析的原理是什么？

A wire is modeled as a series of segments, each having a uniform value of current

电线被建模为一系列段，每个段具有统一的电流值

✓ 正确答案

A wire is modeled as a single sine-wave current generator

将一根电线建模为单个正弦波电流发生器

A wire is modeled as a single sine-wave voltage source

将电线建模为单个正弦波电压源

A wire is modeled as a series of segments, each having a distinct value of voltage across it

电线被建模为一系列段，每个段上都有不同的电压值

#E9B11🔗

What is a disadvantage of decreasing the number of wire segments in an antenna model below 10 segments per half-wavelength?

将天线模型中的线段数量减少到每半波长 10 段以下有什么缺点？

Ground conductivity will not be accurately modeled

地面电导率将无法准确建模

The resulting design will favor radiation of harmonic energy

由此产生的设计将有利于谐波能量的辐射

The computed feed point impedance may be incorrect

计算的馈电点阻抗可能不正确

✓ 正确答案

The antenna will become mechanically unstable

天线将变得机械不稳定

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FCC E9B - 天线与传输线系统

小节 E9B：天线与传输线系统