5G微带阵列天线 要求：利用介质常数为2.2，厚度为1mm，损耗角为0.0009的介质，设计一个工作在5G的4X4的天线阵列。 评分标准： 良：带宽〈7% 优：带宽〉7%且效率大于60%
1微带辐射贴片尺寸估算 设计微带天线的第一步是选择合适的介质基板，假设介质的介电常数为r，对于工作频率f的矩形微带天线，可以用下式设计出高效率辐射贴片的宽度W，即为：
121()2rcwf
式中，c是光速，辐射贴片的长度一般取为/2e；这里e是介质内的导波波长，即为：
ee
c
f
考虑到边缘缩短效应后，实际上的辐射单元长度L应为： 22ecLLf 式中，e是有效介电常数，L是等效辐射缝隙长度。它们可以分别用下式计算，即为：
1211(112)22rrehw
(0.3)(/0.264)0.412(0.258)(/0.8)eewhLhwh
2.单元的仿真 由所给要求以及上述公式计算得辐射贴片的长度L=19.15mm,W=23.72mm。采用非辐射边馈电方式，模型如图1所示： 图1 单元模型 此种馈电方式，可以通过移动馈电的位置获得阻抗匹配，设馈电点距离上宽边的偏移量为dx,经仿真得到当dx=4mm时，阻抗匹配最好。另外，之前计算出的尺寸得到的谐振点略有偏移，经过仿真优化后贴片尺寸变为L=19mm,W=23.72mm。仿真结果图如图2，图3所示。
3.504.004.505.005.506.006.50Freq [GHz]
-30.00
-25.00-20.00-15.00-10.00-5.000.00dB(S(1,1))HFSSDesign1XY Plot 1ANSOFT
m1m2
m3
Curve InfodB(S(1,1))Setup1 : Sweep
NameXYm14.9500-10.3381m25.0600-10.1725m35.0000-26.9508
图2 S11参数 -200.00-150.00-100.00-50.00 0.0050.00100.00150.00200.00Theta [deg]
-20.00
-15.00-10.00-5.000.005.0010.00dB(GainTotal)HFSSDesign1XY Plot 2
Curve InfodB(GainTotal)Setup1 : LastAdaptiveFreq='5GHz' Phi='0deg'
dB(GainTotal)Setup1 : LastAdaptiveFreq='5GHz' Phi='90deg'
图3 增益图 从图中可以看出谐振点为5GHz，计算的相对带宽为2.2%，增益为5.78dB。 2. 2×2阵列设计 设计馈电网络并组阵，模型图如图4所示。
图4 2×2微带天线阵列 3.504.004.505.005.506.006.50Freq [GHz]
-20.00
-17.50-15.00-12.50-10.00-7.50-5.00-2.500.00dB(S(1,1))HFSSDesign1XY Plot 12ANSOFT
Curve Info
dB(S(1,1))Setup1 : Sweep
图 5 S11参数 由S11参数可以看到2×2阵列天线谐振点为5GHz，且此时的S11=-19dB，说明反射损耗小，匹配良好。相对带宽约为2.8%。
-200.00-150.00-100.00-50.00 0.0050.00100.00150.00200.00Theta [deg]
-40.00
-30.00-20.00-10.000.0010.0020.00dB(GainTotal)HFSSDesign1XY Plot 13ANSOFT
m1
m2m3m4Curve InfodB(GainTotal)Setup1 : LastAdaptiveFreq='5GHz' Phi='0deg'dB(GainTotal)Setup1 : LastAdaptiveFreq='5GHz' Phi='90deg'
NameXYm1-1.000013.9625m2-57.00003.3614m3-90.0000-8.5636m479.0000-6.8066 -28.00-16.00-4.008.009060300-30-60-90-120-150-180150120
HFSSDesign1Radiation Pattern 2ANSOFT
Curve Info
dB(GainTotal)Setup1 : LastAdaptiveFreq='5GHz' Phi='0deg'
dB(GainTotal)Setup1 : LastAdaptiveFreq='5GHz' Phi='90deg'
图 6 方向图 由方向图可以看出2×2阵列天线的增益为13.96dB,第一副瓣电平为-10.6dB，可知组阵能使天线的增益变高。
3. 4×4阵列天线 天线阵列如图7所示：
图7 4×4阵列天线 4.004.254.504.755.005.255.505.756.00Freq [GHz]
-22.50
-20.00-17.50-15.00-12.50-10.00-7.50-5.00-2.500.00dB(S(1,1))HFSSDesign1XY Plot 6
图8 S11参数 -200.00-150.00-100.00-50.00 0.0050.00100.00150.00200.00Theta [deg]
-25.00
-20.00-15.00-10.00-5.000.005.0010.0015.0020.00dB(GainTotal)HFSSDesign1XY Plot 3m1
m2m3
Setup
dx1=
Setupdx1=
NameXYm1-3.000019.9638m232.00008.1731m323.00006.8050
-20.00-10.000.0010.009060300-30-60-90-120-150-180150120
HFSSDesign1Radiation Pattern 1Curve InfodB(GainTotal)Setup1 : LastAdaptivedx1='60mm' Freq='5GHz' Phi='0deg'
dB(GainTotal)Setup1 : LastAdaptivedx1='60mm' Freq='5GHz' Phi='90deg'
图9 方向图 由S11参数图可以看到谐振点在5GHz，反射损耗较小，带宽约为2%。由方向图可以看到增益约为19.96dB，第一副瓣电平为-11.79dB。
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