| Abstract: | A microstrip array antenna with low sidelobe level (SLL) for X-band marine radar is proposed. The antenna is composed of a 32-element patch array and a three-layer near-zero-index metamaterial (NZIM). The IABC-Kmeans algorithm, which combines the improved artificial bee colony algorithm and K-means clustering algorithm, is used to optimize the current amplitude of the array elements to obtain a lower SLL. The NZIM is loaded in front of the array antenna to reduce the beamwidth of the E-plane. The antenna is designed and fabricated. The measurement results show that the gain of the antenna at the center frequency is 22.7 dBi, the SLLs of H-plane and E-plane are ?30.66 dB and ? 26.78 dB respectively, and the half-power beamwidth of H-plane is 5.9°. Compared with the previous similar antenna structures, the antenna has lower SLL under the premise of narrow beam and high gain, which is very suitable for X-band marine radar of small and medium fishing vessels. |
