We propose to increase the sensitivity of the (sub)THz radiation detector using an antenna that will focus electromagnetic energy into the active layers of the detector (e.g. HgCdTe).

• The near field is localized around the gap of the antenna, where the active part of the detector is located.
• We calculated the basic characteristics of the antenna, such as realized far-field gain and radiation patterns for different geometrical and material parameters.
• All parameters were optimized for electromagnetic field amplitude maximization in the gap area. 

Fabricated experimental prototypes of the THz antennas of different geometries, which were also calculated in order to optimize the geometry to the resonance in spectral range of the available in the Institute THz sources.