joshuacp
Member level 4
Hello, everyone:
Nowdays, I'm designing a small antenna that operates at the frequency of 398MHz,linear polarization and the gain is 0dBi. I have searched lots lots of papers relating to the aspect of compact antennas, in which I find that the C-patch antennas can satisfy the size requirement. I followed a paper which is in the attachment. The paper has given most the dimensions of the antenna, except the location of the probe. According to the dimension and scale showed by Fig.3 and Fig.5 in the paper, I got the approximate location. With the dimensions by the paper and some changes of the location of the probe, I got good reflection coefficient results, and the resonant frequencies are approximately the same with the results given by the paper. But the gain performances(about -10dBi and -20dBi) of both the antennas are so poor that the antennas couldn't be used in actual systems while the directivities are still very good. Could you please tell me the reason of the poor gain performance? Is it because of the surface wave? Because the paper gives the reflection coefficient performances without the gain performances, I wonder whether this kind of C-patch antennas has been used in actual systems.
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In the attachment, there are the paper and two geo files performed in IE3D 10. The dielectric constant of the substrate is 4.3, and the height is 1.59mm.
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Added after 6 minutes:
Because the network in our Lab. today is not good. I'm sorry that I couldn't attach the paper with the post. The title's name is
Compact microstrip antennas for personal mobile communication.
You can find it in the IEEE datebase.
Nowdays, I'm designing a small antenna that operates at the frequency of 398MHz,linear polarization and the gain is 0dBi. I have searched lots lots of papers relating to the aspect of compact antennas, in which I find that the C-patch antennas can satisfy the size requirement. I followed a paper which is in the attachment. The paper has given most the dimensions of the antenna, except the location of the probe. According to the dimension and scale showed by Fig.3 and Fig.5 in the paper, I got the approximate location. With the dimensions by the paper and some changes of the location of the probe, I got good reflection coefficient results, and the resonant frequencies are approximately the same with the results given by the paper. But the gain performances(about -10dBi and -20dBi) of both the antennas are so poor that the antennas couldn't be used in actual systems while the directivities are still very good. Could you please tell me the reason of the poor gain performance? Is it because of the surface wave? Because the paper gives the reflection coefficient performances without the gain performances, I wonder whether this kind of C-patch antennas has been used in actual systems.
>
In the attachment, there are the paper and two geo files performed in IE3D 10. The dielectric constant of the substrate is 4.3, and the height is 1.59mm.
>
Added after 6 minutes:
Because the network in our Lab. today is not good. I'm sorry that I couldn't attach the paper with the post. The title's name is
Compact microstrip antennas for personal mobile communication.
You can find it in the IEEE datebase.