3D Multi-mode Frequency Selective Structure Based on Slot Line Unit Cells

In this paper, a novel kind of frequency selective structure using slot line unit cells is presented to exhibit filtering response of high performance. Two examples of traditional frequency-selective surfaces, consisting of a 2D periodical array of crossed-slots (cascaded crossed-slots), are briefly reviewed with a focus on understanding their operating principles and identifying their advantages and limitations. In order to improve the filtering performance, we propose a new kind of 3D frequency selective structures with uniform slot-line unit cells, stepped-impedance slot-line unit cells, and multi-mode absorptive slot-line unit cells respectively. These frequency selective structures can be analyzed by transmission-line theory, and can be obtain the desirable resonances in the designed frequencies. The proposed frequency selective structures have good applications in microwave and millimeter-wave frequencies.