Multitier Omnidirectional Antenna on The Circular Waveguide with The Paired Slots on The Tiers

The multitier slot antenna on a circular waveguide with the main H11 operational mode is presented. A distance between the tiers equals to half of wavelength in the waveguide. The first tier has the transverse half-wave radiating frontal slot. The segment, which connects the frontal slot ends, is perpendicular to the waveguide diametric line along the linear polarization direction of the H11 mode. The second tier has the same slot, but it is at opposite side of the waveguide. Those tiers form the two-tier slot structure with frontal slots. The following every two tiers form another two-tier slot structure with paired slots. The first tier of that structure has the transverse half-wave radiating paired slots which centers are spaced by an angle γ over both sides of the waveguide diametric line along the polarization direction of the H11 mode. The second tier of two-tier structure has paired slots too. The centers of those slots in this tier are spaced by the same angle γ, but the paired slots are located at opposite side of the waveguide. The following two-tier slot structure differs from antecedent structure by the angle γ. The investigation results of azimuthal radiation patterns of such paired slots at different spaced angles γ as well as of the two-tier slot structures are discussed. The omnidirectional slot antenna is offered. It is a combination of the two-tier structure with frontal slots and two the two-tier structures with paired slots. An unevenness of the azimuthal radiation pattern of designed antenna does not exceed 3 dB.