A.O. Manichev - Ph. D. (Eng.), PJSC «NPO Almaz» (Moscow). E-mail: alex_manichev@inbox.ru A.A. Smirnov - PJSC «NPO Almaz» (Moscow). E-mail: yaraathed@gmail.com

Today, active phased array antennas (APAAs) using microwave amplifiers in both transmit and receive channels replace passive phased array antennas (PAAs) in many applications owing to their better performance as compared to PAAs (e.g. level of radiated power and noise figure). Timely and automated diagnostics of APAA element faults is very important for successful design and maintenance of these antennas. In some cases effective methods of contactless diagnostics developed for passive PAAs can be used for this purpose. They are based on the mathematical processing of the signals measured at the PAA output under different conditions (for different sets of phaseshifters - states), in order to determine the amplitude and phase of each PAA element. However, the methods can-t provide the element excitation data for elements with failed phaseshifters. This information can be obtained turning on only the amplifier of the tested element. However, this method has the following disad-vantages. Firstly, the power supply of the APAA under test is unloaded during the experiment. Therefore it is impossible to check the elements in the normal mode of APAA operation. Secondly, the radiation of the other elements of APAA can-t be eliminated in full, and their signals can substantially distort the results of the measurements. In order to address the abovementioned issues, a method of contactless diagnostics of APAA elements was proposed. It makes use of the ability of an APAA to turn on/off microwave amplifiers in separate channels and implements the principles of so-called switching methods of measurement based on the Walsh-Hadamard transform. The analytical expressions for estimation of the measurement errors are presented. The efficiency of the proposed method and the accuracy of the formulae are validated via mathematical simulation.

 

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