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Measured Results |
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As shown by Figure 3, the antenna resonates at approximately 2.1GHz as predicted by the simulation. While the simulation showed a bandwidth of 34.6MHz, our measurements yielded a bandwidth of 20.5MHz. Discrepancy is a result of variations in the dielectric constant and manufacturing. |
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Figure 3: Return Loss
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Figure 4 shows the radiation pattern of the antenna. The measured radiation pattern is tilted due to a misalignment in the chamber during measurement and/or effects from the metal in the motor/stand which rotated it. However, the measurements still agree with the simulations. A maximum gain of 4.3 dB is obtained while the half power beam-width is approximately 82 degrees. For our calculations, we will use the worst case gain of the antenna. At 10 degrees above the horizon, the gain is -5dB. Orbital calculations were made using this visible area, so we can be confident that if the system works with this value, it will work anywhere. |
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Figure 4: Comparison of Simulated and Measured Radiation Pattern |
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Figures 5 and 6 show the vertical and horizontal polarization radiation patterns of the antenna. While the vertical polarization has the results previously discussed, the horizontal polarization has more side lobes and a lower gain. However, the patterns demonstrate that the antenna is partially circularly polarized. |
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Figure 5: Vertically Polarized Radiation Pattern
Figure 6: Horizontally Polarized Radiation Pattern
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References
The Remote Educational Antenna Laboratory (REAL) Project, Carnegie Mellon University, [Online] Available: http://preal.ece.cmu.edu/
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