If my understanding of AC and the generation of electromagnetic radiation is correct, then a complete circuit encapsulating power source and resonator is required (a closed circuit). How then can a "random wire" antenna function, as it is an open circuit with infinite resistance - no current should flow when induced by EM radiation.

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    \$\begingroup\$ The key is to realize "the missing half-side of a monopole antenna" (what people refer to as "the ground", "the reference plane", "the counterpoise", or "image antenna"), is often created by the surrounding objects near the antenna wire, such as a metal plate or the actual Earth soil, which is electrically connected to the radio receiver. And in the worst case scenario when there's no object around a random wire antenna in the free space, still, the circuit ground of the radio receiver itself will become its missing half. \$\endgroup\$ Aug 15, 2020 at 9:52
  • \$\begingroup\$ Thank you. This makes sense. The electrons are displaced by the EM radiation, much as a potential difference in a closed circuit would \$\endgroup\$ Aug 16, 2020 at 9:05

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The path is through electromagnetic radiation. You don't need wired connections to transfer electromagnetic energy. Have you done the obvious, and search "How do antennas work" on YouTube?? There's a bunch of good videos

  • \$\begingroup\$ Yes, all just show a wire going to an antenna, with no mention of the number of cores. My prior assumption was that electromagnetic energy won't be induced without a complete circuit, otherwise it's just like an open switch. \$\endgroup\$ Aug 15, 2020 at 8:31
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    \$\begingroup\$ @Chorlton2080 Think it heuristically: consider a dipole antenna, you can make one by putting two metal plates/wires next to each other, a radio receiver is connected between them. There's no closed loop. It's an open DC circuit. However, EM wave in free space can induce a potential difference between two plates. By measuring it, you can receive signals. If you agree a dipole antenna can work, then, if you replace one plate with a random wire, replace another plate with the circuit ground in the radio receiver, such as a metal wire going to the negative battery electrode, it should still work. \$\endgroup\$ Aug 15, 2020 at 9:16
  • \$\begingroup\$ This helps my understanding. Thank you. \$\endgroup\$ Aug 16, 2020 at 9:06

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