L-band four-ridge ortho-mode transducer

Abstract

The invention relates to an L-band four-ridge ortho-mode transducer. The ortho-mode transducer is a modified index gradually-changing curve loaded with ridge diaphragms and a coaxial excitation structure, the operating frequency is 1-2GHz, and the ortho-mode transducer is applied to a radio telescope L-band receiver system. The ortho-mode transducer is composed of a circular waveguide, a four-ridge waveguide gradually-changing transformation segment, a four-ridge circular waveguide, ridge diaphragms, a short-circuit back cavity, a first coaxial probe and a second coaxial probe, and is characterized in that the diameter of the circular waveguide is designed according to the lowest operating frequency; the four-ridge waveguide gradually-changing transformation segment selects a modified index gradually-changing type impedance transformation mode so as to ensure transmission from a dominant mode of the four-ridge circular waveguide dominant mode to a dominant mode of the circular waveguide; chamfer modification is performed on the four-ridge cross section inside the four-ridge circular waveguide so as to ensure that a phenomenon of mutual interference between the ridge diaphragms does not occur; and a four-ridge waveguide coaxial transformer adopts a coaxial feed mode, and the short-circuit back cavity thereof selects a conical design. Measurement and simulation results of the ortho-mode transducer in reflection loss and isolation are basically identical, and radio astronomical observation requirements can be met.

Description

technical field [0001] The invention relates to an L-band quad-ridge orthogonal mode coupler, which is specially used for a broadband microwave receiver in the field of radio astronomy. Background technique [0002] Ortho-Mode Transducer (OMT, Ortho-Mode Transducer), as an important component to realize dual-polarization antenna-feeder system, has been widely used in satellite communication, radio astronomy and military radar. In the field of radio astronomy, the broadening of the OMT operating frequency band is conducive to the realization of full-band coverage of spectrum resources, which can reduce the division of feed types in each frequency band, improve system efficiency, and reduce equipment costs. [0003] An orthogonal mode coupler (referred to as an orthogonalizer or OMT) is a separate or mixed element for two mutually orthogonal polarized waves. OMT can identify independent signals of two orthogonal main modes on a common port (usually a circular waveguide or squ...

AI Technical Summary

Problems solved by technology

[0007] Due to the characteristics of the waveguide mode distribution, even if the first / second high-order mode resonance of the straight channel of the conventional quadrature is eliminated, the working frequency bandwidth of the quadrature cannot be extended to more than twice the frequency band

Therefore, the common fin line OMT, Boifot type partition-branch synthesis OMT, double ridge transition-branch synthesis OMT, double ridge transition-coaxial output OMT, four-arm synthesis OMT, etc. cannot achieve 2:1 octave in engineering. working bandwidth

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