Drakes Lounge Feb 2024 - repeating FRB detected, Disk Yagi Testing

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[@donwoelz]

Has anyone tried squares instead of discs in the yagi design? The manufacturing costs would, I think, be much lower.

[@alexp8144]

Hi Don, in doing a bit of research, there IS an advantage to Circular over Square Comparison between a rectangular patch antenna and a circu-
lar patch antenna using the simulation results obtained from
CST Microwave studio has been carried out.
Both the antenna configurations show quite good results on perspectives of re-
turn loss, VSWR, gain and radiation efficiency, for Bluetooth band applications.
However, from the perspective of return loss and gain the rectangular patch configuration shows better
performance, while the
circular patch configuration shows better results on bandwidth,
radiation pattern,Lower Side Lobe levels.
( example of 2.45GHz Antennas )
Parameter Rectangular Circular
Return Loss 28.28 dB 22.03 dB
Bandwidth 24 MHz 27 MHz
Directivity 7.267 dBi 7.027 dBi
HPBW 72.2 deg 77.7 deg
Side Lobe -10.5 dB -19.6 dB
Gain 7.119 dB 6.968 dB
Radiation
Efficiency 97% 98%
Total Efficiency 96% 97%
www.ijser.org/researchpaper/A-Comparative-Study-of-Rectangular-and-Circular-Microstrip-Fed-Patch.pdf

[@donwoelz]

Thanks, Alex, that was useful. The differences seem small compared to the cost of manufacturing for those who are budget conscious. I'm considering designs for 21cm hydrogen emissions, so bandwidth is not terribly important to me. The design I have been considering is a turnstile antenna as the driven element with director and reflectors being 'X' shaped and aligned with the crossed dipoles of the turnstile. I'm still figuring out how to use 4NEC2 to model it, so I don't have any predictions yet. Ultimately, I want to construct an array of 4 of these.

[@alexp8144]

Don, its not band-width but Side Lobe Suppression that is the significant difference. What is the goal of having 4 antennas ? How do you wire an array ? Each should have a closely coupled LNA.

[@alexp8144]

H_Line reception is not like satellite signals: With a point source, the smaller the beam width, the greater the signal, but the same will reduce H1 signals. For hydrogen line data, a narrowing beam must be accompanied by a larger antenna capture area ( big dish ) .