The ultra-low sidelobe dipole array of 16-elements

The wideband technique for compensating mutual coupling in a small array is developed and experimentally verified. According to this novel compensative method, characteristics of a collinear and a parallel dipole array of 16 elements with -50 dB sidelobe level are computed. For a collinear dipole array, numerical results indicate that the sidelobe level is better than -46.5 dB within the 15% bandwidth and the optimal sidelobe is -48.5 dB. For a parallel dipole array, the sidelobe level is from -45.4 dB to -47.8 dB within the 15% bandwidth. This paper also discusses error tolerance across a constrained-fed array antenna. A method, in which the different exciting currents have different error tolerance, is adopted and this allows a better error tolerance for a practical ultra-low sidelobe array antenna. Using the above method, the L-band constrained-fed collinear dipole array and parallel dipole array of 16-elements are fabricated and tested. The sidelobe level is maintained below -40 dB within 13% and 12% bandwidth respectively.