This paper presents a 66–76-GHz sparsely-excited phased array antenna with the array of array (AoA) architecture for eliminating the blindness and suppressing the grating lobe when scanning. For the array antennas printed on the thick dielectric layers with high relative permittivity, scanning blindness appears and seriously impacts the radiation performance. To address this issue, the AoA topology is developed first. It finds that the scanning blindness appears due to the coupling of the radiating Floquet modes to the non-radiating surface wave (SW) modes. Therefore, the array is divided into two types of domino subarrays. The inner-phase distributions are introduced into the domino subarrays to break the one-to-one relationship between the Floquet mode and the SW mode. Then, the blindness inside ±60° scanning volume is eliminated by the aperiodic subarrays. Meanwhile, the aperiodic inner-phase distributions enhance the aperiodicity of the array and contribute to suppressing the grating lobe when scanning. Next, the meta-surface-based dipole with the shorted post is chosen as the unit cell for the proposed aperiodic array. Based on these methods, the array achieves the wide-scanning performance of ±60° in the E-plane and ±30° in the H-plane, without the blindness and the grating lobe. Finally, the 16×16 array is built and simulated with the dimension of 32 mm × 32 mm. At the highest operating frequency, the simulated gains are 28.42, 25.17, and 24.01 dBi when scanning to the broadside, 50° in the E-plane, and 30° in the H-plane, respectively. Compared to the ideal gain, it shows that the simulated radiation efficiency is about 84.13%, 62.08%, and 35.23% when scanning to the broadside, 50° in the E-plane, and 30° in the H-plane, respectively. The worst transmission coefficient, i.e., the worst isolation, is −11.97 dB between the central element and its two adjacent elements in the E-plane. The array prototypes are fabricated, and the experiments are carried out to verify the correctness of the principle and design. Compared to existing antenna array designs, due to the employment of the AoA architecture, the proposed antenna achieves 51.30% channel reduction with both blindness-free and grating-lobe-free performance. Meanwhile, due to the regular and periodic subarray spacing, the best realizability is achieved for the sparsely-excited phased array at the millimeter-wave bands. This is valuable for the wide-scanning phased array antennas in the sixth-generation (6G) highly-integrated communication systems at the millimeter-wave bands.

本文提出了一种采用阵列阵列 (AoA) 架构的 66-76 GHz 稀疏激励相控阵天线，用于消除扫描时的盲区并抑制栅瓣。对于印刷在相对介电常数较高的厚介质层上的阵列天线，会出现扫描盲区，严重影响辐射性能。为了解决这个问题，首先开发了 AoA 拓扑。研究发现，扫描盲性的出现是由于辐射Floquet模式与非辐射表面波(SW)模式的耦合所致。因此，该数组分为两种类型的多米诺骨牌子数组。将内相位分布引入多米诺子阵列中，打破了Floquet模式和SW模式之间的一对一关系。然后，通过非周期子阵列消除±60°扫描范围内的盲区。同时，非周期性的内相位分布增强了阵列的非周期性，有助于抑制扫描时的栅瓣。接下来，选择具有短路柱的基于超表面的偶极子作为所提出的非周期阵列的单位单元。基于这些方法，阵列实现了E平面±60°和H平面±30°的宽扫描性能，无盲区和栅瓣。最后搭建16×16阵列并进行仿真，尺寸为32 mm×32 mm。在最高工作频率下，扫描到舷侧、E 平面 50° 和 H 平面 30° 时的模拟增益分别为 28.42、25.17 和 24.01 dBi。与理想增益相比，当扫描到侧边、E面50°和H面30°时，模拟辐射效率分别约为84.13%、62.08%和35.23%。E平面中中心元件与其两个相邻元件之间的最差传输系数，即最差隔离度为-11.97dB。制作了阵列样机，并进行了实验，验证了原理和设计的正确性。与现有的天线阵列设计相比，由于采用了AoA架构，所提出的天线实现了51.30%的信道减少，同时具有无盲和无栅瓣性能。同时，由于子阵间距规则且周期性，稀疏激励相控阵在毫米波频段实现了最好的可实现性。这对于毫米波频段第六代（6G）高集成通信系统中的宽扫描相控阵天线具有重要意义。