Constructive synthesis of antenna arrays

Abstract

The synthesis problem of the radiating system together with the excitation scheme of an antenna array is investigated. The array channels include simple lossless four-terminal networks, the constructive parameters variation of which provides the required radiation pattern (RP) and channel matching. Interchannel coupling in the free space and via the power division system is taken into account. Specially developed the optimization criterion considers all the requirements usually given by radar or communication designers. This criterion provides the formation of the steady RP in the given frequency band and after removing some of requirements it coincides with the known optimization criteria.

It is noted that such an approach to the synthesis problem is especially reasonable in designing the antennas with a simple power division system (PDS), has limited opportunities for the amplitude-phase distribution control, or in PDS modernization, and it allows when keeping a high efficiency, to form the radiation patterns which reach a compromise between contradictory requirements.

The examples of antenna array synthesis with uncontrolled patterns having the excitation schemes with equal-amplitude power dividers or divider based on the quarter wavelengths sections are considered.

In the first case the length and wave impedance of the three transmission line sections connected in cascade in each antenna array channel were varied. In the second case the lengths of (he transforming transmission line sections inserted between the divider outputs and antenna array elements were varied.

Forming various radiation patters, including those with low side lobe level in a bandwidth, is discussed.