Hybrid Beamforming for mm-wave Antenna Subsystems based on Ridge Gap Waveguide Technology

高数据速率和大带宽是5G技术的主要特征之一。这些特性与用户数量的预期增长和有限的频谱相矛盾。利用空间分集是一种很有前途的技术，已被推广用于解决这些问题，使用大阵列在高频。推广的解决方案被称为毫米大规模多输入多输出（MIMO）系统。其中使用大量天线形成指向特定用户的尖锐波束，减少对其他用户的同信道干扰，实现高信噪比的传输。传统的波束形成是在数字域进行的，但是在天线中加入波束开关馈电结构可以显著提高波束形成的性能。波束交换网络和数字波束形成的混合称为混合波束形成。波束交换网络负责广泛地选择一定的覆盖区域（扇区），而数字处理单元可以在选定的扇区内重塑波束。本课题旨在开发一种基于脊隙波导技术的混合波束形成原型。最终的原型应该包括一个数字处理单元，控制多个相同的波束交换网络。每个波束交换网络将负责为辐射选择一个特定的扇区，而数字处理单元将对每个网络应用加权信号来重塑所选扇区内的波束。通过控制每个网络信号的幅值和相位，波束可以自适应地分配给特定的用户。

High data rates and large bandwidths are among the main characteristic of the 5G technology. These features contradict the expected increase in the number of users and the limited spectrum. Using space diversity is a promising technique that has been promoted to solve these issues using large arrays at high frequencies. The promoted solution is referred to as millimeter massive multi-input multi-output (MIMO) systems. In which, a large number of antennas is used to form a sharp beam directed to a specific user to reduce the co-channel interference to other users and allowing the transmission with high signal-to-interference ratio (SNIR). Traditionally, beamforming is done in the digital domain, however, adding a beam switching feeding structure to the antennas can enhance the performance of the beamforming dramatically. The mixture of the beam switching network and the digital beamforming is referred to as Hybrid Beamforming. The beam switching network is responsible for broadly selecting a certain coverage area (sector), while the digital processing unit can reshape the beam within the selected sector. This proposal aims to develop a hybrid beamforming prototype based on ridge gap waveguide technology. The final prototype should include a digital processing unit that controls multiple identical beam switching networks. Each beam switching network will be responsible of selecting a certain sector for the radiation, while the digital processing unit will apply weighted signals for each network to reshape the beam within the selected sector. Through controlling both the magnitude and the phase of the signal applied to each network, the beam can be allocated adaptively to a specific user.