3D-Printed Stripline Housing With Angled Stubs for Low-Loss Signals

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Solution Overview

Problem

Additively-manufactured overhanging surfaces in electrical transmission lines cause degraded performance due to electrical losses, higher-order mode propagation, and signal reflections.

Innovation Solution

An additively-manufactured electrical transmission line is configured with a unitary continuous monolithic design, featuring a conductive stripline and angled stubs within a housing, allowing for surface treatment to reduce roughness and improve performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If additively-manufactured overhanging surfaces are used in electrical transmission lines, then manufacturing flexibility and complex geometry are improved, but electrical performance deteriorates due to electrical losses, higher-order mode propagation, and signal reflections

Engineering Contradiction:

Improvemanufacturing flexibilityVSAvoidelectrical performance

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

Surface treatment is performed as a preliminary action immediately after additive manufacturing while the transmission line is still in the build platform. This allows roughness reduction before the part is removed and used, preventing electrical losses and signal reflections that would occur with as-manufactured surfaces.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent replaces traditional mechanical machining methods with post-manufacturing surface treatment processes such as tumbling, blasting, or polishing. These processes can effectively reduce surface roughness on complex additively-manufactured geometries without requiring complex tooling or assembly disassembly.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Productivity

If additively-manufactured transmission lines are produced with as-built surface roughness, then manufacturing simplicity is improved, but electrical losses and signal reflections increase

Engineering Contradiction:

Improvemanufacturing simplicityVSAvoidelectrical losses

Core Design Contradiction:

ProductivityVSLoss of energy

Solution Approach 1:

Surface treatment is integrated into the manufacturing workflow as a preliminary step before final assembly. The transmission line remains on the build platform during treatment, allowing roughness reduction without adding complex post-processing steps or requiring part disassembly.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The build platform itself serves dual purposes: as the manufacturing substrate during additive fabrication and as the treatment medium during surface roughness reduction. The platform's geometry and material properties enable both manufacturing and surface treatment functions.

Inventive Principle:

Principle #25Self-service

3Reliability

If surface treatment is performed after additive manufacturing, then surface roughness is reduced improving electrical performance, but manufacturing complexity increases

Engineering Contradiction:

Improveelectrical performanceVSAvoidmanufacturing process complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the manufacturing and surface treatment processes into a single integrated workflow. The transmission line is manufactured and treated while remaining on the same build platform, eliminating the need for separate handling, fixture setup, and platform removal steps that would increase manufacturing complexity.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The build platform is designed to serve multiple functions: as the substrate for additive manufacturing, as the medium for surface treatment, and as the support structure during both processes. This multi-functionality reduces the need for additional equipment and simplifies the overall manufacturing process.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 minimizes electrical losses and signal reflections, enhances signal integrity, and facilitates efficient additive manufacturing by reducing surface roughness and avoiding complications from partial sintering.

Implementation Method 1

the treating includes abrasive flow machining of the internal surfaces

Methodology Applied

Scientific EffectAbrasion: Abrasion

Implementation Method 2

air in the cavity functions as a dielectric around the stripline

Methodology Applied

Scientific EffectDielectric: Dielectric

Data Source

PatentUS12573737B2Additively-manufactured electrical transmission line, and method of making

Publication Date: 2026.03.10 RAYTHEON CO

AI summary

An additively-manufactured electrical transmission line is made as a single, unitary continuous monolithic additively-manufactured piece of material, including an outer housing defining a cavity therewithin, a conductive stripline passing through the cavity, and stubs within the cavity electrically coupling the outer housing to the stripline. The stripline may be a flat stripline. The stubs may be angled relative to the stripline, to facilitate surface treatment within the housing, such as abrasive flow machining to reduce surface roughness, which may be part of a method of making the electrical transmission line. The electrical transmission line may be part of an electrical installation including multiple such electrical transmission lines, which may have shapes, including curved shapes, for making desired electrical connections between components.