V. N. Antipov1, V. A. Minakov2, V. V. Mukhin3, A. Yu. Frolov4
1, 2, 4 JSC «V.V. Tikhomirov Professional Equipment Research Study Institute» (Moscow, Russia)
3 JSC Urals Design Bureau «Detal» (Kamensk-Uralsky, Sverdlovsk region, Russia)
1, 4 Moscow Aviation Institute (National Research University) (Moscow, Russia)

1 antipov.v.n@gmail.com, 4 alexey_frolov@inbox.ru

Modern radar systems with active phased array antennas (APAA) are used to form various radiation patterns at reception and transmission to solve the set tasks. However, low-noise amplifiers currently used have a technological variation in parameters, which leads to distortion of the beam pattern shape. Compared to passive antenna arrays, these distortions are of a different nature due to the fact that in APAA the gain can vary widely, while in passive antenna arrays it does not exceed one. In digital APAA, unlike analog ones, the process of forming a radiation pattern is not realized by coherent addition of high-frequency oscillations from various parts of the antenna aperture, but by corresponding operations with digital signals generated in a variety of spatial reception channels. That is, there is a more complete extraction of the information components of the radar signal entering the radar antenna. The field distribution in the antenna aperture for reception and transmission, and, accordingly, the transmitting and receiving radar beams, is controlled separately by sending signals to a plurality of phase shifters, depending on electronic digital keys, which in turn are controlled by the beam control unit (processor).

This article evaluates the effect of non-identical low-noise APAA amplifiers on antenna gain, main beam width, side lobe level of the radiation pattern, and target direction-finding errors.

For the most complete understanding, the structural scheme of the radar with APAA has been considered. The characteristics of the APAA radiation pattern have been evaluated depending on the amplitude-phase characteristics of the array amplifiers. It has been established that, in practical implementation, permissible phase errors can be considered up to 10°, and up to 1.5 dB in amplitude. The estimation of errors in measuring angular coordinates by monopulse radars with the phase method of forming the total-difference radiation pattern of the antenna has been performed. It has been shown that the non-identity of the APAA receiving channels leads to the appearance of systematic and increase random errors in measuring the angular coordinates of the target.

The results obtained make it possible to impose requirements on the permissible deviations of the amplitude and phase characteristics of the APAA amplifier during antenna manufacture and to estimate errors in measuring the angular coordinates of the target when receiving the reflected signal.

Antipov V.N., Minakov V.A., Mukhin V.V., Frolov A.Yu. Influence of nonidentity of the APAA receiving channels on the antenna radiation pattern // Antennas. 2026. № 4. P. 5–13. DOI: https://doi.org/10.18127/j03209601-202604-01

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