3D RF-Substrate Patterning for Impedance Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current 3D printed RF elements and systems lack functional fully 3D printed structures, as they are limited to 2.5D stacks of parallel plane topologies, and existing microstrip transmission lines have constant thickness substrates, which restrict the variation range of characteristic impedance and frequency band rejection.
Innovation Solution
A microstrip transmission line with a dielectric substrate featuring periodic sinusoidal undulations and a conductive strip that modulates width in accordance with substrate height, fabricated using additive manufacturing techniques like stereolithography, to maximize the ratio of conductor width to substrate height, enhancing the variation range of characteristic impedance and frequency band rejection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If constant thickness substrate is used in microstrip transmission line, then manufacturing is simple, but the variation range of characteristic impedance is limited
Solution Approach 1:
The patent transitions from 2.5-D parallel plane topology to fully 3-D printed structures by introducing height modulation of the dielectric substrate. The substrate thickness varies periodically along the transmission line, creating a sinusoidal profile that enables continuous adjustment of characteristic impedance beyond what is possible with constant thickness substrates.
Solution Approach 2:
The patent changes the physical parameter of substrate thickness from constant to variable. By modulating the height of the dielectric substrate periodically, the characteristic impedance can be continuously adjusted along the transmission line, enabling broader impedance variation ranges and improved frequency band rejection.
2Ease of manufacture
If 2.5-D stacks of parallel plane topology are used, then fabrication is easier, but frequency band rejection is insufficient
Solution Approach 1:
The patent employs full 3-D printing capabilities to create height-modulated dielectric substrates with sinusoidal profiles. This third-dimensional modulation enables superior frequency band rejection by creating periodic variations in electromagnetic field distribution, which cannot be achieved with conventional 2.5-D parallel plane structures.
Solution Approach 2:
The patent introduces sinusoidal curvature in the substrate height profile, creating smooth periodic undulations rather than flat surfaces. This curved geometry modulates the electromagnetic fields periodically, enhancing frequency selectivity and rejection characteristics while maintaining manufacturability through additive processes.
3Adaptability or versatility
If conductor width modulation is added to height modulation, then characteristic impedance variation is maximized, but device complexity increases
Solution Approach 1:
The patent combines conductor width modulation with height modulation of the dielectric substrate in a unified 3-D printed structure. Both modulations work synergistically to maximize characteristic impedance variation, with the conductive strip following the sinusoidal profile of the substrate while also varying in width to achieve optimal impedance control.
Solution Approach 2:
The 3-D printing process serves multiple functions simultaneously: it creates the dielectric substrate, modulates its height, forms the conductive strip, and controls the conductor width. This multi-functional approach achieves complex impedance variation without requiring separate manufacturing steps for each feature.
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 significantly increases the rejection of specific frequency bands by up to 43 dB, achieving improved performance through the addition of height modulation in the substrate, allowing for more efficient filtering and electromagnetic coupling.
Implementation Method 1
Because the photopolymer resin is photosensitive under ultraviolet light, the resin solidifies when exposed to the UV light to form a layer of the solid resin in the desired pattern
Data Source
AI summary
A microstrip transmission line comprising a dielectric substrate including a series of periodic sinusoidal undulation portions defining spaced apart peaks and troughs, where a distance between the peaks and troughs defines a period of the microstrip line, and where each peak defines a maximum height of the substrate and each trough defines a minimum height of the substrate. The transmission line further includes a conductive strip formed to a surface of the substrate so that the conductive strip follows the undulation portions. The conductive strip includes a modulation portion in a width direction of the conductive strip perpendicular to a signal propagation direction along the strip, where the modulation portion includes a minimum width portion provided at each peak and a maximum width portion provided at each trough so that a variation of a ratio between the width of the conductive strip and the height of the substrate is maximized.