Stealth antenna having electromagnetic wave absorber with sandwich structure

A stealth antenna comprising:

• an electromagnetic wave absorbing structure having a sandwich structure including an upper dielectric layer, a spacer and a lower dielectric layer so that the electromagnetic wave absorbing structure has an absorbing band determined by a dielectric constant and a thickness thereof, the absorbing band being a frequency range of electromagnetic waves that the electromagnetic wave absorbing structure is able to absorb;
• and
• an antenna patch embedded in the electromagnetic wave absorbing structure and disposed between the spacer and the lower dielectric layer,
• wherein
• the upper dielectric layer includes a dielectric fabric and a conductive coating layer coated on a portion of the dielectric fabric so that the upper dielectric layer has a first area where the conductive coating layer is disposed, and a second area where the conductive coating layer is not disposed, the second area overlapping the antenna patch in a plan view such that the conductive coating layer is absent from an area above the antenna patch, the dielectric fabric including first fibers arranged along a first direction and second fibers arranged along a second direction perpendicular to the first direction,
• wherein the lower dielectric layer includes a dielectric fabric impregnated with a resin and having a dielectric constant lower than that of the upper dielectric layer,
• wherein the spacer is disposed and entirely continuous between the upper dielectric layer and the lower dielectric layer, the spacer including a porous foam formed of a resin,
• wherein an operating frequency of the stealth antenna overlaps the absorbing band of the electromagnetic wave absorbing structure,
• wherein a sheet resistance of the upper dielectric layer is 350 ohm/sq to 400 ohm/sq.