Traveling Wave Tube (TWT) RF Interaction Structure from China
RF interaction structure (helix assembly) for traveling wave tubes used in satellite communications and high-frequency amplifiers. Falls under HTS 8540.99.4000 as specified for microwave tubes in 8540.71-8540.79. Enables electron beam interaction for RF signal amplification.
Duty Rate — China → United States
37.5%
Rate breakdown
9903.88.0325%Except as provided in headings 9903.88.13, 9903.88.18, 9903.88.33, 9903.88.34, 9903.88.35, 9903.88.36, 9903.88.37, 9903.88.38, 9903.88.40, 9903.88.41, 9903.88.43, 9903.88.45, 9903.88.46, 9903.88.48, 9903.88.56, 9903.88.64, 9903.88.66, 9903.88.67, 9903.88.68, or 9903.88.69, articles the product of China, as provided for in U.S. note 20(e) to this subchapter and as provided for in the subheadings enumerated in U.S. note 20(f)
9903.05.3112.5%Section 301 (forced labor) — additional 12.5% ad valorem on products of China
Import Tips
• Provide frequency range and power specs in import docs to confirm microwave tube compatibility
• ITAR/EAR export controls often apply; ensure proper licensing and end-user statements
• Test for vacuum integrity if applicable, as customs may inspect for contamination risks