A C-band broadband ortho-mode transducer for radioastronomy polarimetry

Author(s)

Ferreira, Ivan S. ; Tello, Camilo ; Bergano, Miguel ; Villela, Thyrso ; Barbosa, Domingos ; Smoot, George F.

• Document type: Journal article
• Source: SPRINGERPLUS; v. 5, DEC 2 2016.
• Web of Science Citations: 0

Abstract

Background: We describe the design, the construction and performance of a narrow band ortho-mode transducer, currently used in the 5 GHz polarimetric receiver of the Galactic Emission Mapping project. Results: The ortho-mode transducer was designed to achieve a high degree of transmission within the 400 MHz of the GEM band around the 5 GHz (4.8-5.2 GHz). It is composed of a circular-to-square waveguide transition, a septum polarizer, a thin waveguide coupler and a smooth square-to-rectangular waveguide transition with custom waveguide bends to the output ports. Conclusion: Our simulations and measurements show a very low level of cross-polarization of about -60 dB and a good impedance match for all three ports (S11; S22; S33 < -30 dB) with only 0: 25 dB of insertion loss offset across the 400 MHz (4.8-5.2 GHz) of the reception bandwidth. (AU)

• FAPESP's process: 00/06770-2 - The cosmic microwave background radiation (CMBR) and structure formation in the universe
• Grantee: Reuven Opher
• Support Opportunities: Research Projects - Thematic Grants