Frequency-independent wideband horn antenna

Out-of-phase horn antennas with a constant beam width in the H-plane are widely used in the construction of antenna systems for monitoring sources of radio emission with vertical polarization. However, horns that are dephased in the E-plane produce distorted radiation patterns with a high level of side lobes. Such a significant difference in the shape of the radiation patterns is explained by the different nature of the amplitude distribution of the field in the aperture: in the E-plane, the amplitude is constant, and in the H-plane, the amplitude decreases to zero towards the periphery of the aperture ac-cording to the cosine law. To operate on horizontal polarization, feed-through polarizers are usually installed in the aperture of horn antennas, which complicates the design and limits the scope of horns. The article proposes a method for constructing frequency-independent E-sectoral or pyramidal horn antennas with waveguide excitation.

In the pyramidal or E-sectoral horn there are conducting plates-partitions installed orthogonally to the vector E and located symmetrically with respect to the longitudinal axis of the horn. The outer edges of the plates divide the aperture into N equal parts to form a linear equidistant array. The inner edges of the plates are placed with an uneven step near the top of the horn to divide the microwave energy in the horn into N parts in accordance with the cosine distribution law of the field strength in the aperture. The simulation results are presented, confirming the possibility of forming almost constant-width radiation patterns in the frequency band with a relative overlap of 2.25:1. For pyramidal horns with a square opening, it is possible to form equal-sized frequency-independent radiation patterns in both main planes with a stable position of the phase center. The all-metal construction with waveguide excitation ensures the emission of a high level of microwave power in the case of the use of horns as part of transmitting antenna systems. For receiving antenna systems for monitoring the electromagnetic environment, a stable level of intersection of partial patterns with a constant steepness of the direction finding characteristics is maintained. The technical solution for constructing the antenna is patented.