Sliding Stripline Phase Shifter With Via Shielding and Tapered Overlap
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Solution Overview
Problem
Existing stripline phase shifters in RF front ends face issues such as large return loss, increased volume, and weight due to shielding, as well as mechanical misalignment, which affect performance.
Innovation Solution
The implementation of a trombone-type stripline with shielding by vias and an upper ground plane, along with tapered sliding and fixed portions, and non-linear striplines, to enhance mechanical alignment and reduce return loss and insertion loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If shielding is added to the trombone-type stripline phase shifter, then electromagnetic interference is reduced, but volume and weight increase
Solution Approach 1:
The patent implements shielding by nesting vias within the existing stripline structure. The vias are positioned to surround the sliding stripline, creating an electromagnetic shield that is integrated into the phase shifter's compact form rather than adding external shielding structures. This nested approach provides interference protection while maintaining the original volume constraints.
Solution Approach 2:
The patent transitions from traditional planar shielding to three-dimensional shielding using vertically extending vias. By utilizing the vertical dimension (z-axis) with vias that extend through the substrate, the patent creates electromagnetic shielding without increasing the horizontal footprint, thus reducing the overall volume compared to conventional shielding approaches.
2Object-affected harmful factors
If traditional shielding structures are used, then electromagnetic interference is reduced, but weight increases
Solution Approach 1:
The patent replaces traditional bulky metallic shielding structures with thin-film vias that are etched and filled into the substrate. These via-based shields are essentially thin conductive structures that provide electromagnetic shielding with minimal added mass, effectively substituting heavy shielding materials with lightweight conductive pathways.
Solution Approach 2:
The patent utilizes composite construction by combining the substrate material with conductive via materials to create an integrated shielding structure. This composite approach allows the shielding function to be achieved through the existing structural materials rather than adding separate heavy shielding components, thereby reducing overall weight.
3Ease of manufacture
If fixed and sliding portions have the same width, then manufacturing is simplified, but performance degrades due to mechanical misalignment
Solution Approach 1:
The patent introduces asymmetric width relationships between the fixed stripline portion and the sliding stripline portion. The fixed portion is designed with a wider width than the sliding portion, creating an asymmetric overlap region. This asymmetric design provides tolerance compensation for mechanical misalignment while maintaining manufacturing feasibility through standard PCB fabrication techniques.
Solution Approach 2:
The patent applies different width characteristics to different portions of the stripline structure. The fixed portion has a wider width to provide alignment tolerance, while the sliding portion has a narrower width optimized for movement. This local differentiation of geometric properties optimizes both alignment robustness and phase shift performance without complicating the overall manufacturing process.
4Device complexity
If linear striplines are used, then design is simpler, but phase shift per unit motion is reduced
Solution Approach 1:
The patent employs curved or non-linear stripline geometries instead of straight linear paths. The striplines are designed with specific curvature profiles that increase the overlap area between the fixed and sliding portions as the sliding portion moves. This curved geometry amplifies the phase shift effect per unit of mechanical displacement, providing greater phase shift range without increasing the physical size of the device.
Data Source
AI summary
Sliding phase shifters for use in phased array antennas are disclosed. According to one aspect, a sliding phase shifter includes a fixed dielectric having first striplines to couple power into the sliding phase shifter. The sliding phase shifter also includes a sliding dielectric having second striplines electrically slidingly coupled to the first striplines. An amount of phase shift is determined by an amount of overlap of the first striplines and the second striplines, a width of the second striplines being at least partially tapered along a portion of the second striplines to improve performance.