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Question about hexagonal patch antenna frequency and design

Shirpo

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Hi, I'm learning to design a hexagonal patch antenna with 2.4 GHz, so far I only find these example and document as how to design one. It look like there is a set formula to calculate the resonance frequency of the hexagonal patch, so I want to ask why they add the mini 25.24mmx7.46mm to the patch in the picture, wouldn't that make the formula to calculate the frequency incorrect. Or is there some way to determine the resonance frequency of hexagonal patch antenna before designing.
Thank you
1618267864653.png
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vfone

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The step 25.24mmx7.46mm is added for improving impedance matching of the patch.
If you feed the hexagonal patch on one of its corners you don't need any step match, and also improve the patch radiation performance by better current distribution.
 

Shirpo

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The step 25.24mmx7.46mm is added for improving impedance matching of the patch.
If you feed the hexagonal patch on one of its corners you don't need any step match, and also improve the patch radiation performance by better current distribution.
May I ask does improve impedance matching mean It is also improve return loss and achieve the resonant frequency?
And what does step match mean? Does that mean I don't necessary need to follow the formula to calculate the hexagonal patch's frequency?
Sorry I'm still new to this so please help me.
 

vfone

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Yes, impedance matching term refers improving return loss, but this doesn't affect the resonant frequency (hopefully), resonance which is given by the dimensions of the patch antenna.
This step match improve the transition impedance from the feed line to the impedance of the hexagonal patch itself, when this is fed on one of its lateral sides.
Compared to a rectangular patch (which by design could have a near 50 ohms impedance on its side) the hexagonal patch has higher impedance (than 50 ohms) on its lateral sides, and may need a type of impedance matching to the feedline.
But if the hexagonal patch is fed from one of its corners, may don't need any impedance matching circuit if the patch dimensions are chosen properly.
 

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