Beam Mode Expansion of Corrugated Conical Horns with Phase Correcting Lens: Application to Radioastronomy Receivers

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• 作者：Garcí ; a ; E. ; De Haro ; L. ; O'Sullivan ; C. ; Cahill ; G. ; Ferná ; ndez ; J. A. Ló ; pez ; Tercero ; F. ; Galocha ; B. ; Besada ; J. L.
• 关键词：beam mode expansion ; quasi ; optical systems ; radioastronomy ; radiotelescope
• 刊名：Experimental Astronomy
• 出版年：2003
• 出版时间：2003
• 年：2003
• 卷：15
• 期：3
• 页码：173-193
• 全文大小：574 KB
• 刊物类别：Physics and Astronomy
• 刊物主题：Physics
  Astronomy
  Statistics for Engineering, Physics, Computer Science, Chemistry and Geosciences
  
• 出版者：Springer Netherlands
• ISSN：1572-9508

文摘

A classical radioastronomy receiver is fed with a corrugated horn and an independent lens, both placed in a cryostat to lower the noise temperature. The beam is focused and directed using a combination of elliptical and plane mirrors. This paper proposes modifying the initial feeding system by placing the lens onto the horn aperture, thereby allowing a size reduction of the horn and lens, and a simplification of their mechanical design. The profiled lens is shaped to correct the phase error on the horn aperture. A quasi-optical model of the horn-plus-lens system has been developed using a Beam Mode Expansion (BME). Results using both a hyperbolic-planar lens and a spherical-elliptical lens, as well as results obtained by using Geometrical Optics (GO) with a Kirchoff–Huygens integration to get the far-field pattern, have been compared with measurements. As a direct application, a full focusing system for the new 40-m radiotelescope at the “Centro Astronómico de Yebes” is presented for the 22, 30 and 45 GHz bands. This paper has developed a QO model for a corrugated conical horn with a phase-correcting lens.