Phased Arrays Using Odd Phase Distribution of the Radiating Elements

Abstract

We show generation of an asymmetric far-field radiation pattern for uniform linear and planar arrays using phase only excitations that belong to a family of odd functions of the form $\frac{{{{({2{\boldsymbol{\pi }}{{\boldsymbol{b}}_0}})}^{2{\boldsymbol{n}} + 1}}({{{\boldsymbol{x}}^{2{\boldsymbol{n}} + 1}} + {{\boldsymbol{y}}^{2{\boldsymbol{n}} + 1}}})}}{{2{\boldsymbol{n}} + 1}}$ , where ${\boldsymbol{n}} = 1,2,3, \ldots$ . The mainlobe and the dominant sidelobes are contained in one quadrant of the azimuthal plane, whereas the sidelobes in the remaining three quadrants are reduced significantly (by 9 dB at least, for the considered array size). In comparison, such an asymmetric radiation pattern is unlike the symmetric pattern produced by a conventional uniform phased array. The asymmetrical sidelobe distribution is achieved while maintaining the mainlobe intensity and beamwidth. In addition to the odd phase excitations, applying the Chebyshev amplitude modulation further enhances the sidelobe asymmetry, also increasing the array directivity. The designed phased arrays have good scan performance from $ - 45^\circ $ to $45^\circ $ in the elevation and azimuth planes with an ability to maintain constant directivity. Such asymmetrical radiation patterns could easily reject interfering signals and ground clutter, which is beneficial in many radar and communications applications.