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
对于工作频率 即为: 步是选择合适的介质基板,假设介质的介电常数为 &r,
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,
式中,C
波长,即为: 是光速,辐射贴片的长度一般取为 飞/2 ;这里e是介质内的导波
考虑到边缘缩短效应后,实际上的辐射单元长度 L应为:
L —C -2 丄
2 f •. ;e
式中,
计算,即为: ;e是有效介电常数,厶L是等效辐射缝隙长度。它们可以分别用下式
1
Er +1 Er —1 h -5
;e (1 12 ) 2
2 2 w
.丄"412h(;e。①⑶川 °264)
® —0.258)(w/h+0.8) 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=4mmP寸,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。
Freq [GHz]
图2 S11参数 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 X 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 X2微带天线阵列 图5 S11参数
由S11参数可以看到2X 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%。Name XY Plot 13 HFSSDesig n1
-1.0000 13.9625
m2 -57.0000 3.3614 ml
m3 -90.0000 -8.5636
TO.oo 79.0000 -6.8066
m2 Curve Info
____ dB(GainTotal)
Setup1 : LastAdaptive
Freq='5GHz' P hi='0deg'
____ dB(GainTotal)
Setup1 : LastAdaptive
Freq二'5GHz' P
0.00 —
m3 m4
a -10.00
-20.00
-30.00 一
-40.00 —|i
-200.00 -150.00 -100.00 -50.00 0.00 50.00
Theta [deg] 100.00 150.00 200.00 Freq [GHz]
Curve Info .dB(GainTotal) Setup1 :
LastAdaptive Freq='5GHz' P
hi='0deg' dB(GainTotal)
Setup1 : LastAdaptive Freq='5GHz'
P hi='90deg'
图6方向图
由方向图可以看出2X 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 X 4阵列天线
天线阵列如图7所示: Radiation Pattern 2 HFSSDesig n1 ANSOFT 图74 X4阵列天线
m2 5.0560 -10.4730 dB(S(1,1))
Setupl : Sw eep
dy='12mm'
6 00
图8 S11参数
目
d—
nRadiation Pattern 1 HFSSDesig n1
Curve Info
____ dB(GainTotal)
Setup1 : LastAdaptive
dx仁'60mm' Freq='5GHz' P hi='0deg'
---- dB(GainTotal)
Setup1 : LastAdaptive
dx仁'60mm' Freq='5GHz' P hi='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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