The Triple Feed Patch antenna is a directional circularly polarized antenna that was created with the main design goals of:
- Good radiation efficiency. Most FR4-based patches have terrible efficiency because FR4 is very lossy at 5.8 GHz.
- Good axial ratio, not just directly perpendicular to the patch but also off-center.
- Cheap and easy to manufacture with high accuracy, even for a hobbyist.
Specs:
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Center frequency: 5.8 GHz
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Bandwidth: 660 MHz (5.47 – 6.13 GHz)
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Matching: S11 < -20 dB, VSWR < 1.22 (at center frequency)
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Axial ratio: < 1.3
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Antenna gain: 9.4 dBi
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Half power beam width: 55° (horizontal and vertical)
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Radiation efficiency: 83.5%
These values are based on simulation, actual measurements are below (they are very similar). The center frequency may shift a bit between batches as a result of variations in the dielectric constant of FR4. Also, not all brands of FR4 have the same dielectric constant. Frequency shifts up to 100 MHz are normal.
Designed by: Maarten Baert & Robin Theunis