多通道DDS基板隔离度设计与优化

Design and Optimization of Substrate Isolation for Multi-channel DDS

随着多通道DDS采样频率的提高,保证通道间的高隔离度成为基板设计中的难题。本文利用Ansys HFSS软件对一款采样频率为2.5GHz的四通道DDS陶瓷基板进行设计,建立了芯片和基板的协同仿真模型,选取基板的通道间耦合间距、信号孔与接地孔比、地平面布局三个参数作为优化因子,进行隔离度优化仿真。测试结果表明通道间实现了在1GHz以内的隔离度优于70dB,为四通道DDS在雷达信号源中的应用提供了技术支撑。

As the improvement of multi-channel DDS sampling frequency,ensuring high isolation between channels becomes a difficult problem in the design of substrate.In this paper,Ansys HFSS software was used to design a four-channel ceramic substrate with a sampling frequency of 2.5 GHz,and a co-simulation model of the chip and the substrate was established.Three parameters of the coupling spacing between the channels of substrate,the ratio of signal hole and ground hole,and the ground plane layout ware selected as the optimization factor for the isolation of optimizing simulation.The measured results show that the isolation between channels is better than 70 dB within 1 GHz,which provides the technical support for the application of four-channel DDS in radar signal source.