Fig. 7: Structural design, analyses, and microwave energy transmission performance of a twist bellows EM waveguide.

a A twist WR-284 EM waveguide (left) as the baseline model and the fabricated bellows waveguide in extended (center) and compressed configurations (right). b 2D crease pattern adopted to fabricate the twist bellow model. c Plot of rotation per half-unit (ρ/M) vs. deployment angle (ψ) for different cut angles (α). d Plot of normalized deployment length per half-unit (D_n/M) vs. deployment angle (ψ) for different cut angles (α). e Plot of rotation per half-unit (ρ/M) vs. normalized deployment length per half-unit (D_n/M) for different cut angles (α). f Comparison of analytical and experimental curves showing the relationship between rotation angle and deployment length. g The relationship between the cut angle (α) and the required number of half units (M) to reach 90˚ twist at its nominal length. h, i Simulated electric field distributions at the central frequency (left) and the S₂₁ vs. frequency relation, comparing the baseline WR-284 twist waveguide with the twist bellows waveguide. j Experimental S₂₁ vs. frequency relations as a comparison between the WR-284 twist waveguide and the fabricated twist bellows waveguide. Scale bars: 60 mm.