Segmented Magic Tee Junction for Broadband Port Matching

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Solution Overview

Problem

State-of-the-art magic T microwave junctions operate over a limited frequency band and suffer from imperfect port matching and isolation, with improvements in one plane often degrading performance in the other plane.

Innovation Solution

A magic T-shaped microwave junction is split into a three-port E-plane T junction and a three-port H-plane T junction, allowing independent optimization of each, with symmetrical waveguides and metallic elements for adjustment, and produced using metal additive manufacturing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If metallic elements such as pads or matching screws are added to the waveguide connection point of a magic T microwave junction to improve port matching and operating frequency band, then port matching and bandwidth are improved, but the complexity of fabrication increases and improvements in one plane tend to have negative repercussions in the other plane

Engineering Contradiction:
Improveport matchingVSAvoidfabrication complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The magic T junction is segmented into two separate T-shaped microwave junctions (E-plane and H-plane) that are coupled together. This segmentation allows each junction to be optimized independently for its respective plane, avoiding the trade-off where improvements in one plane degrade performance in the other plane. The separate optimization of each T-junction eliminates the need for complex metallic elements while achieving superior overall performance.

Inventive Principle:
Principle #1Segmentation

2Adaptability or versatility

If metallic elements such as pads or matching screws are added to the waveguide connection point of a magic T microwave junction to improve port matching and operating frequency band, then operating frequency band is improved, but the complexity of fabrication increases

Engineering Contradiction:
Improveoperating frequency bandVSAvoidfabrication complexity
Core Design Contradiction:
Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

By segmenting the magic T junction into two independent T-shaped microwave junctions, each can be optimized for broader bandwidth operation without requiring additional metallic elements. The independent optimization of each junction's geometry allows for enhanced frequency band adaptability while maintaining simple fabrication processes.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Each T-shaped microwave junction is designed with local geometric optimizations tailored to its specific plane (E-plane or H-plane). This local quality approach allows each junction to achieve optimal performance for its designated function, resulting in an overall broader operating frequency band without requiring complex metallic additions that would complicate manufacturing.

Inventive Principle:
Principle #3Local quality

3Adaptability or versatility

If the three-arm structure of E-plane and H-plane T-junctions is used, then the functions of E-plane coupler and H-plane coupler are achieved, but port matching is imperfect

Engineering Contradiction:
Improvecoupling functionVSAvoidport matching
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

Two separate T-shaped microwave junctions (E-plane and H-plane) are merged and coupled together to form a magic T junction that simultaneously achieves the coupling functions of both planes while maintaining perfect port matching. The merging of these independently optimized junctions allows each to contribute its specialized coupling capability without compromising the other's performance.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP4024604B1Hyperfrequency junction in broadband magic tee
Publication Date: 2025.09.03 THALES SA
  • EP4024604B1 patent drawingFigure 1a~1b
  • EP4024604B1 patent drawingFigure 1c
  • EP4024604B1 patent drawingFigure 2a~2b

AI summary

The invention relates to a magic T microwave junction comprising: - an E-plane T junction comprising a difference arm (201) along a first axis (Ox) in a reference plane (xOz) and two collinear arms (202, 203) symmetrical with respect to the reference plane, - an H-plane T junction comprising a sum arm (211) along an axis (O'z') orthogonal to the first axis in the reference plane and two collinear arms (212, 213) symmetrical with respect to the reference plane, - two first waveguides (221, 222) symmetrical with respect to the reference plane, connected to the ends of the collinear arms of the junctions, - two waveguides (231, 232) symmetrical with respect to the reference plane and connected to the first waveguides. The invention also relates to a power divider, a beamforming array and a production method by additive manufacturing.