The increasing need to provide new methods for designing smaller electromagnetic devices leads to nanotechnology applications. Substrate integrated waveguide (SIW) while integrated with the system can lead to side lobe level reduction and gain enhancement. In this paper, log-periodic dipole nanoantenna array in terahertz frequencies incorporating SIW at the far-end edge of dipoles and along the feed line is presented. This design results in an improvement of gain and favorable impedance matching in the far infrared band. A bandwidth of 1300 GHz is obtained for the proposed design. The operating frequency is considered to be 1.87 THz corresponding to 166-μm wavelength.
