Surface coating technique for loss in RF structures.

摘要

Extra loss is introduced in coupled cavity and klystron RF circuits by applying a surface coating to selected parts of circuit elements used in the circuits. The coating is applied in the form of a slurry, which is then sintered. The slurry comprises a mixture of an iron-base powder (such as a stainless steel) and a dielectric glass ceramic, suspended in a binder dissolved in a solvent. Circuits with the loss coating are easier to match than by other prior art techniques. The loss coating of the invention reduces the fabrication cost of coupled-cavity traveling wave tubes, while improving the performance by minimizing the gain ripple. Higher average power operation is possible, due to elimination of loss buttons previously employed in the prior art.