Multi-Layered PCB Inductor Structure for High Q Factor
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Solution Overview
Problem
Existing discrete inductors, both fixed-value and variable, lack precision and require significant manual adjustment and space, making them unsuitable for applications like diplexers and triplexers that need sharp-cutoff signal filters with precise inductance values.
Innovation Solution
A multi-layered inductor structure is implemented using spiral inductors on multiple substrate layers, aligned and electrically coupled to reduce skin-effect losses and achieve high Q factor values, allowing for precise inductance values with minimal tolerance and reduced labor and space requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If discrete inductors are used in diplexer and triplexer circuits, then signal filtering can be implemented, but the inductance precision is insufficient (tolerance of approximately 2%)
Solution Approach 1:
The patent transitions from discrete three-dimensional inductor components to planar two-dimensional spiral inductor patterns fabricated on printed circuit board layers. This dimensional change enables precise inductance control through geometric parameters (trace width, spacing, number of turns) that can be accurately controlled during PCB manufacturing, achieving sub-1% tolerance without manual adjustment.
Solution Approach 2:
The patent replaces the mechanical adjustment mechanism of variable inductors (manual winding compression or expansion) with an integrated planar spiral structure where inductance is determined by fixed geometric parameters. This substitution eliminates the need for mechanical adjustment components and manual labor while achieving precise inductance values through controlled fabrication processes.
2Measurement precision
If variable inductors with manual adjustment are used to achieve precise inductance values, then inductance precision can be improved, but labor intensity and manufacturing time increase significantly
Solution Approach 1:
The planar spiral inductor structure is designed to achieve precise inductance values through its geometric parameters alone, without requiring any manual adjustment or post-fabrication modification. The inductance is self-determined by the trace width, spacing, and number of turns, which are controlled during automated PCB manufacturing, thereby eliminating labor-intensive adjustment processes.
Solution Approach 2:
The patent changes the approach to inductance control from mechanical parameter adjustment (physical compression or expansion of windings) to geometric parameter specification (trace dimensions and pattern geometry) that are inherently controlled during fabrication. This parameter transformation enables precise inductance values to be achieved automatically through manufacturing process control rather than manual adjustment.
3Reliability
If discrete inductors are used in circuits, then signal filtering function can be provided, but the space required is significant
Solution Approach 1:
The patent utilizes the planar dimension of the PCB surface to create spiral inductor patterns that generate inductance within the two-dimensional plane rather than requiring three-dimensional wound components. This approach dramatically reduces the footprint area required while maintaining the signal filtering function, as the inductor traces are integrated directly into the PCB layout.
Solution Approach 2:
The patent merges the inductor structure with the PCB substrate itself, integrating the inductive element directly into the circuit board rather than using separate discrete components. This consolidation eliminates the need for additional component mounting space and allows the inductor to share the PCB real estate with other circuit elements, significantly reducing overall space requirements.
4Ease of manufacture
If fixed-value sealed inductors are used, then manufacturing is simplified, but inductance precision is limited to approximately 2% tolerance
Solution Approach 1:
The patent replaces the sealed discrete inductor component with a planar spiral pattern fabricated directly on the PCB using standard PCB manufacturing processes. This substitution maintains manufacturing simplicity by eliminating separate component assembly while achieving superior inductance precision through controlled geometric parameters that can be accurately reproduced during fabrication.
Solution Approach 2:
The patent changes the basis of inductance determination from the physical construction parameters of wound inductors (wire diameter, winding tightness, core material) to geometric parameters of planar traces (trace width, spacing, number of turns, spiral radius) that are inherently more controllable during automated PCB manufacturing, thereby achieving tighter tolerance without complicating the manufacturing process.
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 multi-layered inductor structure achieves high Q factor values and precise inductance with reduced skin-effect losses, enabling efficient implementation in applications like diplexers and triplexers with improved manufacturing efficiency and reduced space usage.
Implementation Method 1
A multi-layered structure for implementing an inductor is provided. The multi-layered structure may include a first planar substrate layer having a first spiral inductor situated on a surface thereof; a second planar substrate layer having a second spiral inductor situated on a surface of the second planar substrate layer; wherein the first and second spiral inductors are electrically coupled to form an overall multi-layered inductor. The multi-layered structure reduces skin-effect losses
Data Source
AI summary
An enhanced multi-layered structure is disclosed including an N number of inductor layers (N is an integer greater than one). Each inductor layer includes a substrate and at least one spiral inductors situated on the substrate. The inductor layers may be stacked and aligned with each other so that the electromagnetic fields of the spiral inductors on different inductor layers overlap (at least partially). The spiral inductors on the various inductor layers may be electrically coupled to each other so as to act at an overall inductor. The substrates may be very thin to reduce losses, increase the inductance, and lower the resistance of the overall inductor. The enhanced structure may further include ground planes disposed on top of and below the N inductor layers to provide shielding for the inductor layers. This enhanced structure enables a low loss, high Q inductor to be implemented in a high-performance circuit.