Energy conversion efficiency improvement device

An accompanying device being used in combination with an energy conversion efficiency improvement device,

• the energy conversion efficiency improvement device comprising:
• a first antenna including a conducting wire wound therein, the conducting wire being connected to a direct-current power source;
• an LC circuit unit connected with the conducting wire of the first antenna, and having at least one LC module including an inductance element and a capacitor element connected in series or in parallel with each other;
• a joined material portion including at least two different kinds of materials joined with each other;
• and
• a horn component including a conductor, formed line-symmetrically with respect to a central axis, and formed in a shape having an external diameter increasing in one direction along the central axis,
• the accompanying device comprising:
• a wound coil;
• and
• a second horn component with an external diameter increasing in one direction provided over or under the coil.