I'm looking to design a system that will require a 2.4GHz antenna. The only problem is, every single reference design I find has the antenna situated on at least one board edge. Unfortunately due to the nature of the design I don't have a board edge available.

Is there any reason I couldn't have the antenna in the center of the board if I ensure the surrounding area is well grounded?

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    \$\begingroup\$ Is your board spherical or toroidal? \$\endgroup\$ – PlasmaHH Jul 16 '15 at 10:33
  • \$\begingroup\$ Or maybe infinitely wide? \$\endgroup\$ – Andy aka Jul 16 '15 at 10:51
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    \$\begingroup\$ think of a tiny connector and an external antenna \$\endgroup\$ – Umar Jul 16 '15 at 10:53
  • \$\begingroup\$ Ensuring the surrounding area is well grounded is likely to make it not work, surely? The PCB antenna designs I've seen have minimum distances to ground planes. \$\endgroup\$ – pjc50 Jul 16 '15 at 11:38
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    \$\begingroup\$ (and Umar has the answer: you can buy 'sample' PCB antennas that come with short micro-coax leads and connectors, usually hirose UFL. \$\endgroup\$ – pjc50 Jul 16 '15 at 11:39

In general antennas need a "clear view" so that the radiated EM waves can "escape". This "clear view" needs to be at least on one side, where else would the waves go ? The antennas on the edge of PCBs are usually omnidirectional antennas meaning they radiate on all sides. A ground plane on one side disturbes this of course but in many cases this is acceptable.

In your case radiating in the plane parallel to the PCB should be avoided as the groundplanes/other components will reflect the radiation and this you want to avoid.

But you do still have 2 sides available ! Up and down ! There are antennas that radiate straight up and down, one example is the patch antenna. However, you have to consider if the limited direction in which the radiation is radiated is acceptable for your application !


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