一种新型路径共享真时延波束合成架构的设计

为满足宽带天线通信系统多输入多输出的要求，提出了一种新型路径共享真时延波束合成架构。通过真时延单元提供的一定延时差弥补信号到达天线的时间差，合成多路信号来提高输出能力。相比于传统的波束合成架构，该架构通过真时延单元共享，节省芯片面积。该架构具有中心对称性与可扩展性，可支持2M个输入和2K个输出。基于HHNEC 0.18 μm CMOS工艺设计四入四出波束合成器单元，对提出的架构加以验证。仿真结果表明，工作频带为0.5~1.5 GHz，延时分辨率为80 ps、最大延时为720 ps。在天线间距为10.5 cm的情况下，能够提供±43°和±13°四个扫描角度。输入输出回波损耗≤-10 dB，带内整体增益为约26 dB，增益平坦度≤3 dB。版图面积（包括I/O焊盘和ESD）为3.69 mm×3.62 mm。 

Design of a new path-sharing true-time-delay beamformer architecture

In order to meet the requirement of multi-input and multi-output of broadband wireless communication system, a new path-sharing true-time-delay beamformer architecture is proposed in this paper. The output capability is improved by synthesizing multiple signals, compensating the time difference in reaching the antenna with a certain delay difference provided by the true-time-delay unit. Compared with the traditional beamformer architecture, this architecture can save the area of chip by true-time-delay unit sharing. It is not only extensional, supporting 2 M antennas and synthesizing 2 K signal beams, but also symmetrical. Based on HHNEC 0.18 μm CMOS process, four-in-four-out beamformer is designed to verify the proposed architecture. The simulation results show that this beamformer works over 0.5-1.5 GHz and has four antennas, with delay resolution of 80 ps and maximum delay of 720 ps. It can provide four scanning angles of ±43° and ±13° for four antennas with 10.5 cm spacing. The input-output return loss is not more than -10 dB, the gain is about 26 dB, and gain flatness is not more than 3 dB. The layout area (including I/O pad and ESD) is 3.69 mm×3.62 mm.