R. S. Orekhov1, N. A. Pavlov2, A. V. Tsareva3

1, 2 JSC “Research Institute “Vector” (St. Petersburg, Russia)

3  St. Petersburg State Electrotechnical University “LETI” (St. Petersburg, Russia)

The results of modeling a multibeam antenna based on a cylindrical Luneburg lens designed for radiomonitoring systems have been presented. The amplitude-phase method of beam width stabilization in the frequency range with an overlap of more than an octave has been implemented in the model. The frequency-dependent phase distribution in the lens aperture with a diameter of 230 mm has been obtained by changing the lens profile with a focus shift of 20 mm. The necessary phase skew to stabilize the beam width was 75, 105, 200 degrees at the frequencies of 8, 12, 18 GHz, respectively. A horn with an aperture of 24x8 mm has been used as an irradiator. The amplitude-phase distribution formed in the lens aperture provided the level of side lobes below –20 dB in the entire operating range.

The application of this method allows for a constant level of intersection of non-adjacent beams with a deviation of not more than ±1 dB in the entire operating frequency range has been shown by the example of an eight-beam antenna with a viewing sector in the azimuthal plane of 60 degrees. At the same time, the beam width at the level of –8 dB lies within 15–17 degrees, and the direction finding characteristic formed by neighboring rays is close to linear, weakly depends on the frequency, and its average steepness is 2 dB/degree.

A multibeam direction-finding broadband antenna based on a cylindrical Luneburg lens, which is effective in terms of the lens antenna aperture efficiency (AAE) maximizing, cannot be realized by forming all the beams in one aperture. The estimation of the lens AAE maximum achievable at placement of all irradiators in one aperture is a subject of further researches. The simulation has been carried out in the electrodynamic modeling package CST Studio.

Orekhov R.S., Pavlov N.A., Tsareva A.V. Multibeam antenna based on a cylindrical Luneburg lens with a stabilized beam. Antennas. 2021. № 6. P. 68–75. DOI: https://doi.org/10.18127/j03209601-202106-07 (in Russian)

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