Very Compact Waveguide Orthomode Transducer in the K-Band for Broadband Communication Satellite Array Antennas.

Area of Science:

• Electromagnetics and Wave Propagation
• Microwave Engineering
• Satellite Communications

Background:

• Orthomode transducers (OMTs) are crucial components in dual-polarized communication systems.
• Existing compact OMT designs often face challenges in manufacturing complexity and performance trade-offs.

Purpose of the Study:

• To introduce a novel, compact waveguide orthomode transducer (OMT) design.
• To demonstrate its suitability for millimeter-wave frequencies and satellite communication applications.
• To validate the design through simulation and measurement.

Main Methods:

• A twofold rotationally symmetric cross-section in the probing area was adapted from a side-coupling OMT design.
• The OMT was designed for the K-band (17.3-20.2 GHz) and integrated with standard WR42 waveguide transitions and a conical horn antenna.
• Performance was evaluated using electromagnetic simulations and anechoic chamber measurements.

Main Results:

• The OMT achieved a fractional bandwidth of 15-20% with low port-to-port coupling (< -22.9 dB) and high cross-polarization discrimination (> 30 dB).
• Measured reflection and coupling coefficients were below -19.5 dB and -22.9 dB, respectively, aligning with simulation results.
• The design's compact nature allows for lattice integration below one wavelength at the highest operating frequency.

Conclusions:

• The proposed compact waveguide OMT offers a simpler design for millimeter-wave frequencies, facilitating easier manufacturing.
• Its performance characteristics make it highly suitable for dual-polarized, closely spaced array antennas in satellite systems.
• The design's mechanical simplicity is advantageous for additive manufacturing techniques.