Tunable Frequency Selective Surface Based on a Sliding 3D-Printed Inserted Dielectric

A novel mechanically tunable frequency selective surface (FSS) based on a sliding 3D-printed inserted dielectric is presented in this paper. This paper first introduces the working mechanism of the tunable FSS, which indicates that the variable capacitance is the key to tunability. Based on this, we design an all-metal bandpass FSS with a certain thickness and a matching cross-shaped inserted dielectric. By changing the insertion depth of the dielectric, the resonance frequency can be adjusted. To optimize the performance, an improved structure based on a hollow support and a tripole slot is proposed. A tunable range from 3.24 to 5.52 GHz (53%) and good angular stability is obtained in the simulation. To verify this idea, we fabricate a cross slot prototype by 3D printing and mechanical engraving. Measured results show that this prototype has a continuous tunable range of 3.61 to 5.89 GHz (34.4%).