I am trying to use meander shape coil on PCB for wireless power transfer, with no luck so far. The primary coil is meander shape on PCB, receiving coil is a loop of wire with a tuning cap. Both RLC circuits tuned for 740Khz.I would like to induce at least 0.5V at 1cm. I have successfully resonantly coupled secondary coil with THT drum coil I only have a problem with PCB coil.

  1. Can I connect another inductor in series with primary coil to increase its inductance and will it affect electromagnetic field around PCB coil?

  2. How to make electromagnetic field stronger on PCB coil other than increasing current?

  3. When designing meander PCB coil is it better to make more turns, less spacing between them and thinner lines or wide lines and bigger spacing?

  4. Does higher inductance mean bigger field surrounding coil?

  5. Should Both RLC circuit be impedance matched and how crucial it is?

Edit: picture added, drum inductor added to increase inductance. enter image description here

  • \$\begingroup\$ Magnetic field is proportional to ampere-turns. You can either increase the current, or increase the number of loops on your PCB (or both). \$\endgroup\$
    – Dave Tweed
    May 8 '17 at 18:33
  • \$\begingroup\$ This shouldn't be a problem but without a picture who knows why it doesn't work properly or what your expectations are? \$\endgroup\$
    – Andy aka
    May 9 '17 at 7:34

A meander structure (it's not a "coil") is very inefficient for creating a magnetic field by electric currents because adjacent currents go in opposite directions, i.e. magnetic fields cancel out.

It's much more effient to use a real coil structure (e.g. spiral), i.e. adjacent currents will go in the same direction, i.e. magnetic fields add up.

  • \$\begingroup\$ The reason I chose meander is because I want the magnetic field to be horizontal to PCB. \$\endgroup\$
    – J.Doe
    May 9 '17 at 10:50
  • \$\begingroup\$ @J.Doe: see Biot-Savart law. The fact that magnetic field is the result of current (density) vector cross multiplied by position vector means that it is perdendicular to both of them. \$\endgroup\$
    – Curd
    May 9 '17 at 11:06
  • \$\begingroup\$ If you want to limit the field to one side of the board you might look at an electronic version of a Halbach Array. However, that would be a tricky research project and probably not do-able in 2D \$\endgroup\$ May 9 '17 at 11:23
  • \$\begingroup\$ what about double sided PCB coil, with a shape similar to wounded coil? \$\endgroup\$
    – J.Doe
    May 9 '17 at 14:10
  • \$\begingroup\$ One trace on one side another on the other, and so on. \$\endgroup\$
    – J.Doe
    May 9 '17 at 14:17

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