Coaxial-to-Waveguide Power Combiner with Matching Plate
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Solution Overview
Problem
Existing power combiners and dividers, especially those with multiple coaxial ports and a single waveguide port, face challenges in efficiently handling high-power electromagnetic energy and maintaining symmetry to minimize power reflection, which is crucial for combining or dividing signals effectively at RF, microwave, and millimeter-wave frequencies.
Innovation Solution
A coaxial-to-waveguide power combiner/divider design featuring a closed waveguide with a conductive end plate and a matching plate that transforms electromagnetic fields while maintaining N-fold rotational symmetry, ensuring equivalent ports and minimizing reflected power, allowing for efficient high-power signal combination or division.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If multiple coaxial ports are combined with a single waveguide port to handle high-power applications, then the power handling capability is improved, but the device complexity increases
Solution Approach 1:
The waveguide end plate is segmented into multiple holes to accommodate N coaxial ports, while the matching plate is divided into N identical segments arranged with N-fold rotational symmetry. This segmentation allows the complex multi-port device to be constructed from repeated simple unit cells, managing complexity through modular design while achieving high power handling capability.
Solution Approach 2:
The device serves multiple functions: it combines N coaxial power inputs into a single waveguide output, divides waveguide power into N coaxial outputs, and maintains N-fold rotational symmetry for equivalent port performance. The matching plate structure provides universal applicability across different power combining scenarios.
2Reliability
If N-fold rotational symmetry is maintained to ensure equivalent ports and minimize reflection, then the power reflection is reduced, but the manufacturing precision requirements increase
Solution Approach 1:
While the overall structure maintains N-fold rotational symmetry, the matching plate is positioned at a specific asymmetric distance from the end plate, and the coaxial ports are oriented with their outer conductors touching the end plate at specific angular positions. This controlled asymmetry within a symmetric framework achieves both reflection minimization and manufacturability.
Solution Approach 2:
The design optimizes specific parameters including the distance between the matching plate and end plate, the diameter of coaxial port holes, and the spacing between adjacent ports. By carefully selecting these parameters, the device achieves N-fold rotational symmetry that minimizes reflection while remaining manufacturable with standard tolerances.
3Reliability
If the matching plate is positioned spaced apart from the end plate and inner walls, then the electromagnetic field transformation is improved, but the device volume increases
Solution Approach 1:
The matching plate is positioned in the longitudinal dimension (spaced from the end plate) rather than expanding the transverse dimensions. This allows effective electromagnetic field transformation to occur along the waveguide length without significantly increasing the overall device volume, as the spacing is optimized to be minimal while still achieving the required field transformation.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution enables efficient transportation and transformation of high-power electromagnetic energy with minimal reflection, ensuring all ports operate equally and maintain symmetry, thereby maximizing combined output power and operational bandwidth.
Implementation Method 1
the matching plate transforms the electromagnetic fields emerging from the each of the N coaxial inputs into a form that propagates in the waveguide
Implementation Method 2
limiting the power reflected back towards the N sources whose outputs are combined
Data Source
Figure 1a~1c
Figure 2
Figure 3
AI summary
To transport electromagnetic energy at high power levels, a coaxial-to-waveguide power combiner/divider (10) comprises a length of single-conductor closed waveguide (16) terminated at one end by a conductive end plate (18). A plurality N of holes (22) is formed in the end plate. A conductive matching plate (26) is positioned within the waveguide opposite and spaced apart from the conductive end plate and spaced apart from the inner walls of the waveguide. A plurality of coaxial input/output ports (12) each comprise an outer conductor (24) that is electrically and mechanically terminated at the end plate about one hole and an inner conductor (20) that extends through the associated hole into the waveguide and is electrically and mechanically terminated at the underside of the matching plate. The location and geometry of the matching plate and physical arrangement of the N ports are chosen so that the sum of the direct reflection and the N-1 coupled reflection contributions are small.