Ultrawide Band Antenna and Filter Design
Ultrawide Band Antenna and Filter Design
Ultrawide Band Antenna and Filter Design
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14<br />
The basic of antenna Gain, efficiency <strong>and</strong> directivity<br />
Spherical radiation<br />
Balloon becomes<br />
spherical<br />
0dBi<br />
Blow air 1 into antenna<br />
The spherical shape is radiation pattern<br />
What’s that<br />
making gain<br />
higher?<br />
If try to break balloon?<br />
The volume of blown air is constant<br />
Integration value of directional pattern =1<br />
<strong>Antenna</strong> efficiency 100%<br />
Unit of gain → dBi (i→isotropic)<br />
-α(dB)<br />
It means that isotropic antenna is st<strong>and</strong>ard antenna for gain<br />
measurement.<br />
This is the ideal antenna that radiates equally in all directions.<br />
1<br />
dBd<br />
dBic<br />
dBil<br />
+α(dB)<br />
2005/11/3
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