Research Progress on Micromachining Technologies Used to Fabricate Terahertz Micro-Metallic Rectangular Cavity Structures.

Terahertz metal rectangular cavity structures are widely used in terahertz devices due to their performance advantages, and various microfabrication techniques have been applied to the manufacturing of their high performance. In this paper, several typical application fields of terahertz technology and the reasons for its application in these fields are elaborated in detail. Several typical terahertz devices with terahertz metal rectangular cavity structures are introduced in detail. The research progress of various micromachining techniques for manufacturing terahertz rectangular cavity structures, such as DRIE, UV-LIGA, micro-milling, LTCC, 3D printing, and electrochemical micromachining, is discussed in detail. Finally, the advantages and disadvantages of various micromachining techniques for manufacturing terahertz micro-rectangular cavity structures are discussed, and the results show that electrochemical micromachining technology and micro-nano 3D printing technology are relatively promising methods for the manufacturing of high-frequency terahertz rectangular cavity structures.