The characteristic directivity of the linear equidistant invariant antenna array (IAA) in the band of frequencies has been investigated. The given antenna array allows to form 2 beams guided in space and 1 radiation pattern gap guided in space. Moreover, the location of the formed gap doesn’t depend on the frequency within antenna operating frequency range.

The analysis of radiation pattern form in the band of frequencies showed that the gap in the radiation pattern is formed in the given direction and doesn’t depend on the frequency within antenna operating frequency range. The change of frequency distorts the form of the beams of the radiation pattern greatly. This distortion is found out to be caused by the base filters IAA includes. The base filters form the gap in the given direction of the radiation pattern.

It’s possible to get rid of dependence of the beam form of the radiation pattern on the frequency on a certain location of the beams in space and the gap.