非均匀间距的低副瓣宽带微带阵列天线设计

为降低天线副瓣电平（SLL）和展宽带宽，设计了一款谐振频率为14.25 GHz的16阵元非均匀间距的耦合馈电微带阵列天线。天线采用多层设计，通过在接地板开矩形槽进行耦合馈电，并引入空气层，降低天线Q值，增大带宽。区别于均匀间距阵列天线的激励幅值加权，从阵元间距角度入手，利用差分进化算法降低副瓣电平，构建非均匀间距并联线阵天线。用槽面辐射的能量近似代替阵元接收的能量，观察阵元功率分配情况，并建立馈电网络所有馈线段的数学关系，保证非均匀间距条件下所有阵元为等幅同相激励。测试结果显示，天线在14~14.5 GHz范围内电压驻波比小于2，满足了卫星动中通的带宽要求；工作带宽内增益大于16 dB，副瓣电平低于-16 dB，性能优于均匀间距阵列天线。 

Design of low sidelobe broadband microstrip array antenna with non-uniform spacing

To reduce the Sidelobe Level (SLL) of the antenna and widen the bandwidth, a 16-element coupled-feed microstrip array antenna with non-uniform spacing at 14.25 GHz frequency was designed. The antenna adopts a multi-layer design, and a rectangular groove is formed in the ground layer to perform coupling feeding. And the air layer is introduced to reduce the antenna Q value and increase the bandwidth. Different from the excitation amplitude weighting of uniformly spaced antennas, this paper starts from the perspective of array element spacing, differential evolution algorithm is used to reduce the SLL, and a non-uniform spacing parallel linear array antenna is constructed. The energy received by the array element is approximately replaced with the energy passing through the rectangular slot, and the power distribution of the array element is observed. And the mathematical relationship of all feeder sections of the feed network is established to ensure that all array elements are excited with equal amplitude and in phase under the condition of unequal spacing. The measurement results show that the antenna has a voltage standing wave ratio of less than 2 in the range of 14 GHz to 15.2 GHz, which satisfies the bandwidth requirements of satcom on the move. The gain is more than 16 dB and the SLL is less than -17 dB within the operating bandwidth, which shows that the performance is better than that of the array antenna with uniform spacing.