volume | PIER Journals

Abstract

The paper presents array-pattern synthesis for wide-band nulling at specified directions. The projection matrix method is invoked to obtain an orthogonal operator matrix (OOM). The OOM transforms a quiescent excitation vector to an optimally modified excitation vector that warrants ideal nulls at the desired directions at multiple frequencies. However, the modified excitation does not provide the optimal solution for a shaped beam, particularly near the edge-of-coverage region. We obtain an improved shaped beam solution by determining a complete set of orthonormal basis vectors that represent the column space of the OOM. Optimum amplitudes of the basis vectors yield an improved shaped beam. The method is amended for nulls in phased array-fed reflector (PAFR) antenna patterns. The method does not require explicit determination of eigenvalues and eigenvectors, thereby enhancing the computation efficiency facilitating easy implementation in a digital processor. As a consequence, real time nulling in phased arrays and PAFRs are feasible with minimal computation burden, appealing to communication satellites.

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doi:10.2528/PIERM24080403

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Dr. Arun K. Bhattacharyya