A Suggested Arrangement of Grooves for Enhancing the Return Loss Performance Characteristics of Submillimeter-Wave Corrugated Horns

[摘要] Anewarrangementofgroovesbywhichthereturnlossperformancecharacteristicsofsubmillimeter-wavecorrugatedhornshavebeengreatlyimprovedispresented.Corrugatedhornsequippedwithgroovesarrangedasperthewayintroducedinthispapereachhavebeenfoundtobecapableofradiatingafieldwithreturnlossesof$$-$$28orlessdB,whilemaintainingmaximumcross-polarizationlevelsof$$-$$45orlessdBwithinafrequencyrangeof385GHzto500GHz.Thisisaperformancelevelgreaterthanthegoalsetforfeedhornsforradiotelescopes.Thereasonforthisenhancementofthereturnlossesisbecausethepartoftenreferredtoasthe“mode-transformingsection”hasbeenformeddifferently,thatistosaythegroovesarearrangeddifferentlyinthispartthanintheconventionalmode-transformingsection.Specifically,thenumberofgroovesprovidedinthisnewmode-transformingsectionhasbeendecreasedvis-à-visthatofthoseintheconventionalmode-transformingsection,andthesegroovesarearrangedwiththeirdepthsvariedinaccordancewiththeanglesofthesection’sflares.Further,thestructureofeachgroovehasbeensosimplifiedthatitisaparallelogramincrosssection,andthepartoutsidethemode-transformingsectionisprovidedwithgroovesthatareinuniformdepthandwidthbeingarrangedataregularinterval.Despitethesimplicityofthegrooves,thereturnlossesofsubmillimeter-wavecorrugatedhornshavebeengreatlyenhancedwhiletheircross-polarradiationfieldsaremaintainedatlowlevels.

[学科分类] 天文学(综合)

[关键词] "instrumentation: miscellaneous";"mode-transforming sections";"techniques: submillimeter";telescopes;terahertz-waves