Corrugated Multi-Layer Microwave PCB Weight Reduction
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Solution Overview
Problem
Conventional multi-layer printed circuit boards (PCBs) are too heavy and complex for next-generation active arrays in space and airborne applications, such as micro-satellites and stratospheric airships, due to the use of full sheets of bond ply adhesive film, which hinders weight reduction while maintaining structural strength.
Innovation Solution
A multi-layer microwave corrugated printed circuit board design featuring a first flat flexible layer and a second folded flexible layer with non-conductive adhesive layers and through-holes for interconnects, forming a corrugated structure that reduces weight and enhances structural integrity by using arches similar to corrugated fiberboard, allowing for lighter and more conformal assemblies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If full sheets of bond ply adhesive film are used to laminate circuit layers together, then structural strength is maintained, but weight increases significantly
Solution Approach 1:
The adhesive film is segmented into discrete adhesive regions rather than using full sheets. The adhesive layers are applied only in specific regions where bonding is required, such as at the edges or at discrete points, leaving large portions of the circuit layers unbonded. This segmentation dramatically reduces the total amount of adhesive material while maintaining sufficient structural strength for the panel assembly.
Solution Approach 2:
The bonding structure transitions from uniform full-sheet adhesive coverage to localized adhesive regions. Adhesive is applied only where structurally necessary, creating different bonding densities in different areas of the panel. This local quality approach optimizes the balance between structural integrity and weight reduction by concentrating adhesive material in high-stress regions.
2Strength
If conventional JCB construction is used for multi-layer mixed signal panels, then structural integrity is achieved, but device complexity and weight increase
Solution Approach 1:
The conventional JCB (Joiner-Circuit Board-Joiner) construction is segmented and simplified. Instead of complex multi-component joiner assemblies, the patent uses direct adhesive bonding between circuit layers with simplified interconnect structures. The bonding structure itself is divided into discrete adhesive regions rather than requiring continuous adhesive coverage, reducing manufacturing complexity.
Solution Approach 2:
Complex joiner components and intermediate structural elements are extracted from the assembly. The patent eliminates the need for separate joiner pieces and complex lamination procedures by using direct adhesive bonding between circuit boards. This extraction of unnecessary components simplifies the overall construction while maintaining structural integrity.
3Weight of moving object
If lighter weight materials and structures are used, then weight reduction is achieved, but structural strength may be compromised
Solution Approach 1:
The bonding structure is segmented into discrete adhesive regions concentrated at structurally critical locations such as panel edges and high-stress areas. This segmentation allows the use of lighterweight circuit board materials while maintaining overall panel strength, as the adhesive is strategically placed only where needed to support the reduced-weight structure rather than providing uniform bonding across the entire panel surface.
Solution Approach 2:
The adhesive bonding provides localized structural reinforcement at critical regions while allowing the majority of the panel to use lighterweight materials. This local quality approach enables weight reduction in non-critical areas while maintaining sufficient strength through targeted adhesive application at load-bearing regions.
Data Source
AI summary
A multi-layer microwave corrugated printed circuit board is provided. In one embodiment, an interconnect assembly includes a first flat flexible layer having a signal conductor and a ground conductor forming a first microstripline or microstrip transmission line, a second folded flexible layer having a signal conductor and a ground conductor forming a second microstripline or microstrip transmission line, the bottom surface of the second folded flexible layer having ridge portions, a non-conductive adhesive layer disposed between the top surface of the first flat flexible layer and the ridge portions of the second folded flexible layer, a signal through-hole extending through the non-conductive adhesive layer and the first flat flexible layer, and two ground through-holes extending through the non-conductive adhesive layer and the second folded flexible layer, wherein the two ground through-holes are disposed on opposite sides of the signal through-hole.