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The datasheet for this chip antenna shows a couple of radiation plots, but I don't know how they correspond to the physical orientation of the antenna.

radiationpatterns

I want to orient the antenna so that the nice, omnidirectional "co-pol H-Plane" is parallel to the ground. For example, say I placed the device on a table in a room. I don't care how well it radiates above or below the table, but I want to be able to walk in a circle around it and always get consistent signal strength.

Are the angles (\$\theta\$ and \$\phi\$) standardized? I've seen other datasheets (for different antennas) that show the corresponding orientation, but I'm stuck with using this one.

In other words: Should I orient the antenna "side-to-side", or "up-and-down"? :)

Thanks.

bitsmack
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3 Answers3

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to elaborate on the answer from Zokol...
Wikipedia image

If you have a vertical (up-down) antenna, the H field is horizontal, as in the picture from the Wikipedia page Zokol mentioned.
I would have made this a comment, but I wanted to include the actual image rather than just link to it.

Alan Campbell
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The H-plane refers to horizontal, and E-plane to vertical radiation orientation. Co-pol stands for co-polarization, meaning that the transmitter and receiver are using same polarization orientation. Cross-polarization means that the polarization of the transmitter is inverted, comparing to the receiver. For example: sending signal with left-hand circular polarization, when the receiver is designed for right-hand circular polarization. Similar effect with horizontal vs. vertical polarization.

So you should place the antenna horizontaly and keep the other antenna oriented so that the polarization is not inverted.

Sources: https://en.wikipedia.org/wiki/E-plane_and_H-plane http://www.antenna-theory.com/definitions/crosspolarization.php

Zokol
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    Thank you, that's helpful. However, I believe that the H-plane can be either horizontal _OR_ vertical, depending on the polarization of the antenna. This would also be true with the E-plane. So, I guess my real question is: is there enough information in the datasheet to determine how the antenna is polarized with respect to it's physical orientation? – bitsmack Dec 04 '14 at 23:23
  • You are absolutely right, I missed the fact mentioned in the Wikipedia article "For a vertically polarized antenna, the H-plane usually coincides with the horizontal/azimuth plane. For a horizontally polarized antenna, the H-plane usually coincides with the vertical/elevation plane." – Zokol Dec 05 '14 at 06:35
  • According to the datasheet, the antenna is omni-directional on azimuth. Based on that fact, I would say that the H-plane is on horizontal orientation. – Zokol Dec 05 '14 at 06:45
  • Horizontal relative to what? The question is how to mount the chip to get a horizontal H-plane. From the proportions on the antenna, it seems like the board will sit in the E plane. So if you want an H plane parallel to the ground, you will need to mount the board vertically. – alex.forencich Dec 05 '14 at 08:11
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H-plane is the plane in which the magnetic fields propagate and E-plane is the plane in which the electric fields propagate. In a standard vertical dipole antenna, the H plane is perpendicular to the axis of the antenna while the E plane is any vertical plane that passes through the antenna (electric field lines from one end of the antenna to the other follow the E-plane while magnetic field lines circulating around the antenna follow the H plane).

My guess is that this chip is more or less an electrically lengthened dipole, so if you want vertical polarization (H plane parallel to the ground), you will have to stand it up on its end and mount your board vertically. Otherwise the physical proportions of the antenna don't really make much sense.

alex.forencich
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