EAPSI: Making small, low loss, metallic-magnetic heterostructures for next generation devices

磁系统在微波频率范围内对于许多通信和雷达系统有用的许多设备应用是有价值的。应用包括隔离器和其他信号处理器件。隔离器特别需要磁性材料来产生非互易传播，即允许信号通过信号线在一个方向上传播，但相反方向被阻挡。减小信号线元件的尺寸对于向元件的微芯片生产移动是必要的。减小磁性部件的尺寸的限制之一是金属结构中固有的大功率损耗。已经有许多建议来限制小型磁系统中的功率损耗，包括使用非金属磁体。该项目将模拟一种金属磁性和非金属材料的光栅结构，以减少功率损耗。磁性结构将在新加坡国立大学Adeyeye博士的实验室制造，该实验室是磁性纳米纤维的领先实验室之一，并将进行实验测量。实验和理论结果将被比较。金属薄膜在微波场的存在下产生涡流。通过使用光栅而不是连续的金属膜，涡流损耗可以显著降低。该项目的目标是开发一个理论模型，使用分析技术以及数值模拟，如有效介质理论和有限元建模，以预测在波导中添加电介质和金属磁性光栅结构的效果。为了实现低损耗的非互易传输，将对光栅的不同取向、磁化方向和偏振进行分析和优化。这个NSF EAPSI奖是与新加坡国家研究基金会合作资助的。

Magnetic systems are valuable in the microwave frequency range for a number of device applications useful for many communications and radar systems. Applications include isolators and other signal processing devices. Isolators specifically necessitate magnetic materials to create nonreciprocal propagation, i.e. a signal is allowed to propagate in one direction through a signal line but the reverse direction is blocked. Decreasing the size of the signal line components is necessary to move toward microchip production of components. One of the limitations to decreasing the size of the magnetic components is the large power losses inherent in metallic structures. There have been a number of proposals to limit the power losses in small magnetic systems including using non-metallic magnets. This project will model a structure with a grating of metallic-magnetic and non-metallic materials to decrease power losses. The magnetic structure will be fabricated at Dr. Adeyeye's lab at the National University of Singapore, one of the leading labs for magnetic nanofabrication, and experimental measurements will be taken. Experimental and theoretical results will then be compared.Metallic films generate eddy currents in the presence of microwave fields. By using a grating rather than a continuous metallic film eddy current losses can be significantly reduced. The goal of this project is to develop a theoretical model using analytical techniques as well as numerical simulations, such as effective medium theory and finite element modeling, to predict the effect of adding a dielectric and metallic-magnetic grating structure into a waveguide. A number of different orientations of grating, magnetization direction and polarization will be analyzed and optimized for nonreciprocal propagation with low losses. This NSF EAPSI award is funded in collaboration with the National Research Foundation of Singapore.