Canadian TV, Computing and Home Theatre Forums - View Single Post - Scatter Forager - wide pattern bi-directional "Slot" antenna

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post #3 of (permalink) Old 2010-07-18, 10:36 AM Thread Starter
ota_canuck
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Join Date: Mar 2009
Location: Dunnville, Ontario on the Grand River, North shore Lake Erie
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Yes, thanks to the inspirations of Alan Blumlein in 1938. The basic working principal is that the sheet is the ground plane and the hole is actually the working antenna. The difference in this application is that the mesh [call it the reflector or ground plane] helps to gather/integrate multipath signals.

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A slot antenna consists of a metal surface, usually a flat plate, with a hole or slot cut out. When the plate is driven as an antenna by a driving frequency, the slot radiates electromagnetic waves in similar way to a dipole antenna. The shape and size of the slot, as well as the driving frequency, determine the radiation distribution pattern. Slot antennas are often used instead of line antennas when greater control of the radiation pattern is required. Slot antennas are often found in standard desktop microwave sources used for research purposes.

A slot antenna's main advantages are its size, design simplicity, robustness, and convenient adaptation to mass production using PC board technology.

The slot antenna was invented in 1938 by Alan Blumlein, while working for EMI. He invented it in order to produce a practical type of antenna for VHF television broadcasting that would have horizontal polarization, an omni-directional horizontal radiation pattern and a narrow vertical radiation pattern
http://en.wikipedia.org/wiki/Slot_antenna
Aperture antenna [aka: slot, free field antennas] designs are widely used by NASA for radar, communications, satellite, ground stations, etc. In theory, we should be able to use a single panel and make one aperture for VHF 7-13 and another aperture for 14-51. But, that doesn't work in the real world. In my design the ground plane mesh is dimensioned for VHF-Hi reception and the aperture is set to recieve UHF

As I stated in the OP.
Quote:
"Here's something interesting"

3D SSH III with ZZ4 refl. http://imageshack.us/user/jmsdigital
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