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I am designing a low-cost ($5) transceiver based remote system, that uses a CC110L or rfm22b type transceiver (i.e. low cost). What are some cost-effective, yet high performance antenna options? My goal here is to maximize range (minimize antenna losses), and range is more important than bit-rate.

Goals:

  1. Antenna efficiency of >70%, larger is better

  2. Omnidirectional (as much as possible)

  3. Space constraints: must fit within 25cm x 150cm area

The options I'm considering are:

  1. A simple wire seems to be the easiest, but performance might not be good.

  2. An off-the-shelf PCB-mount antenna (SMD chip, helix, etc)

  3. PCB trace antenna

    a. whip design

    b. helix

    c. dipole

    d. others?

The preferred option here is PCB trace antenna due to cost reasons...so kind of focusing on that.

Using a standard FR-4 2-layer standard-spec PCB, is it possible to design a high-performing PCB trace antenna?

What type of PCB trace antennas would be the best and why? Helical? Whip? Others? Are there any good reference designs or guidelines to design this type of 433MHz PCB trace antenna?

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closed as too broad by Chris Stratton, uint128_t, Leon Heller, Andy aka, RoyC Mar 2 '18 at 10:28

Please edit the question to limit it to a specific problem with enough detail to identify an adequate answer. Avoid asking multiple distinct questions at once. See the How to Ask page for help clarifying this question. If this question can be reworded to fit the rules in the help center, please edit the question.

  • \$\begingroup\$ This question is, of course, far too broad to fit the stack exchange format. It is also underspecified. A wire dipole can be a decent antenna - if you have the space for it. Many antennas are compromise designs intended to be either compact, or to work over a range of frequencies rather than a single one. \$\endgroup\$ – Chris Stratton Mar 2 '18 at 3:52
  • \$\begingroup\$ Directionality? Balanced (dipole) or unbalanced (monopole) output drive circuit? Polarization issues? \$\endgroup\$ – Andy aka Mar 2 '18 at 10:19
  • \$\begingroup\$ This is going to be in a keychain, so directionality is every possibility (perhaps not upside down unless the user is laying down). The output drive is dipole on these chips, at least on the TI ones. \$\endgroup\$ – Adam B Mar 2 '18 at 16:42
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You cannot ask for good unless you define what is good for gain in each direction of XYZ.

Define it just like an illumination design with intensity needed to have error free reading in defined directions.

This is a space diversity tradeoff with gain and omnidirectional 0dBi only exists on paper.

If you cannot define priorities for the design; cost range, performance range, size range; so that suitable tradeoffs can be made to meet all 3 , then the solution cannot be defined. If they are realist and can be defined then meeting the spec makes it perfect.

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  • \$\begingroup\$ Thanks for the answer and feedback.. I've added additional details as far as requirements. \$\endgroup\$ – Adam B Mar 2 '18 at 9:35
  • \$\begingroup\$ Let me be more clear. Which directions do you want to be poor and unreliable. All antenna have these \$\endgroup\$ – Sunnyskyguy EE75 Mar 2 '18 at 14:35
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Antenna performance heavily depends on the size of the radiating element relative to the wavelength. As your antenna gets shorter than \$\frac{1}{2}\lambda\$, the gain starts dropping, as well as the radiation resistance of the antenna going down, making it harder to connect the antenna to your transmitter.

Since 433 MHz has a wavelength of approximately 70cm, your antenna should be about 35cm long for best performance. Your pcb is probably not going to be that large, so your best bet would be to use a wire antenna if at all possible

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