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PATCH ANTENNA ARRAY

The Patch Antenna Array was constructed and used for various satellite up and down links at my previous residence in Melbourne, Victoria from 2003 - 2007


Patch antenna developed for 436MHzThe patch antenna developed for 436MHz by Greg (VK3BLG) in 2003 is a remarkable antenna for amateur satellite work. The four element antenna array has demonstrated about 16dbi gain, a remarkable figure for its compact size. The truncated cut to the radiating elements creates the Right Hand Circular (RHC) radiation pattern ideal for most amateur satellite communication.

Intended to work as the up link antenna for AO40 my version was only used on two occasions with excellent results before the demise of AO40 in early 2004.  

I operated the patch array antenna from 2003 to mid 2007 as a completely steerable array and have been able to consistently manage contacts through the UO14 and more recently AO51 satellite down to the horizon with very solid contacts down to 5 degrees above the horizon. Signal strengths of 5/9 on occasions, but typically 5/5 for most passes.

The main disadvantages of the patch array as I see it is that it has a very narrow band width, is not easily adjustable and while not a large problem for satellite work where the antenna need not be installed in a high and exposed location is its high wind loading due to the unavoidable large surface profile.  

 

 

DIAGRAM OF SINGLE FEED CIRCULAR POLARISED PATCH ANTENNA (Truncated Corners) TOP VIEW

Frequency:                 436.0 Mhz

Polarisation:               Right Hand Circular

Patch Material:           2 mm Aluminium

Patch Sides:              316mm (Resonates at 436Mhz)

Patch Height:             17mm above Ground Plane

Patch Mounting:         6 mm nylon bolts using 3 nuts as spacers 75 mm diagonally from each patch corner (prior to truncation)

Ground Plane:            At least 50mm larger all around the patch i.e. for a patch 316 x 316 mm, the Ground Plane should be about

                                 416 x 416 mm        

75 Ohm Point:           0.115 Wavelengths from the centre ( 79.0 mm for 436.0 Mhz)

Truncation:                40.0 mm

 

Element centre to centre spacing: 0.77 Wavelength or 530mm  

DIAGRAM OF SINGLE FEED CIRCULAR POLARISED PATCH ANTENNA (Truncated Corners)  TOP VIEW

 

 

 

 

 

 

 

 

 

 

Rear view of the patch array as constructed for 436MHz.

Rear view of the patch array as constructed for 436MHz.

436MHz power divider.

  Rear view of the patch array as constructed for 436MHz

436MHz power divider

 

DIAGRAM OF FOUR WAY POWER DIVIDER

Frequency:                 436.0 MHz    

Feed point:                 50 Ohm Point ('N' Connector)

Four feed out points:   75 Ohm Point ('F' Connectors) Feeds to patches - 75 Ohm RG6 (One electrical wavelength long)

 

 

DIAGRAM OF FOUR WAY POWER DIVIDER

 

 

 

For more information on the patch antenna developed for 436MHz by Greg (VK3BLG). May you rest in peace.

 

See:  Preparatory material for an article published Amateur Radio (Wireless Institute of Australia's national magazine). 

Article Part#1 Patch Antenna Pt1 

Article Part#2 Patch Antenna Pt2

 

Rules for patch antennas designs. See: Patch Antenna Rules

 

For more information on patch antennas. See: http://en.wikipedia.org/wiki/Patch_antenna

 

Patch Antenna Calculator See: http://www.emtalk.com/mpacalc.php

 

Microstrip Patch Antenna Tutorial and Simulator. See: http://www.emtalk.com/tut_1.htm

 

 

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Page last revised 14 July 2010  
 

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