Flap attenuator

{{Short description|Waveguide component}}

File:Flap attenuator- wiki.png

The flap attenuator or resistive-card attenuatorIntegrated Publishing's Educational Archive [https://armymunitions.tpub.com/mm50058/mm500580191.htm armymunitions.tpub.com] is a flap-type waveguide attenuator that allows for precise and continuous attenuation of electromagnetic waves traveling through a rectangle waveguide.

It comprises a thin, disk-shaped attenuation material that extends through a longitudinal slot in the middle of the wider side of the waveguide into the inner space of the waveguide. The extent of the insertion is variable, and the attenuation can be made approximately linear with the insertion by properly shaping the resistance card. A shape with as few sharp edges as possible is considered to minimize reflections. As a rule, semicircular, thin panes are preferred.Department of ECE, Rohini College of Engineering & Technology [https://rcet.org.in/uploads/academics/rohini_26697761285.pdf EC8701 Antenna and Microwave Engineering]

The attenuation can be typically up to 30 decibels. In the millimeter wave range, it's possible to achieve up to 40 dB. [https://www.worldradiohistory.com/Archive-Catalogs/Suppliers/ABC/Amperex%20%20Catalog%20%20Microwave%20tubes%20%20%20%20%2012%20pages.pdf Amperex Catalog Microwave tubes] The attenuation is frequency-dependent, resulting in less attenuation of harmonics for complex signals.Igor Ya. Belyaev, [https://www.researchgate.net/profile/Igor-Belyaev/publication/3122074_Comments_on_Nonthermal_effects_of_extremely_high-frequency_microwaves_on_chromatin_conformation_in_cells_in_vitro-dependence_on_physical_physiological_and_genetic_factors_-_Reply/links/54dc6fb10cf23fe133b171b6/Comments-on-Nonthermal-effects-of-extremely-high-frequency-microwaves-on-chromatin-conformation-in-cells-in-vitro-dependence-on-physical-physiological-and-genetic-factors-Reply.pdf Reply to comments] in Bioelectromagnetics 18:529–530 (1997)