The effects of chemical modification of the carbon nanotubes (CNTs) due to injection of the boron or nitrogen atoms on the electromagnetic properties of CNTs are studied. The calculation of the band structure of carbon nanotubes modified chemically is performed using the linear augmented cylindrical wave method. Semiclassical model for the dynamics of electrons is used to calculate the linear conductance of CNTs. To investigate the antenna characteristics of CNT a scattering of plane electromagnetic wave on CNT is considered and a boundary problem for Maxwell’s equations is analyzed. It is demonstrated that the substitution of carbon atoms for boron or nitrogen is an effective way to improve antenna characteristics of CNTs.