Planar Balun Design Using Multilayer PCB for Bandwidth Expansion
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Solution Overview
Problem
Conventional baluns are time-consuming and costly to manufacture due to their complex machining processes, and they have limited operation bandwidth.
Innovation Solution
A planar balun design using substrates and ground layers with a common ground element, allowing for easy manufacturing via multilayer PCB or LTCC processes, and tuning of line widths to increase bandwidth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional machining process is used to manufacture balun, then manufacturing precision can be achieved, but manufacturing time and costs increase significantly
Solution Approach 1:
The patent replaces the conventional mechanical machining process with a planar structure fabrication process using PCB or LTCC technology. Instead of mechanically cutting and assembling three-dimensional components, the invention uses printed circuit board manufacturing techniques to create the balun structure on flat substrates, significantly reducing manufacturing time while maintaining precision through standardized fabrication processes
Solution Approach 2:
The invention transitions from a three-dimensional cylindrical structure to a two-dimensional planar structure. By laying out the feed conductor, ground elements, and common ground element on flat substrates in specific geometric patterns, the balun achieves its function through planar geometry rather than mechanical three-dimensional form, enabling easier and faster manufacturing
2Strength
If conventional machining process is used to manufacture balun, then structural integrity can be ensured, but manufacturing costs increase
Solution Approach 1:
The patent replaces expensive mechanical machining and assembly operations with cost-effective PCB or LTCC fabrication processes. These standardized manufacturing methods use automated printing, lamination, and firing processes that are inherently more economical than custom mechanical machining, while the resulting layered structures provide sufficient structural integrity for the balun's application
Solution Approach 2:
The invention uses composite construction with multiple layers of substrate material, conductive traces, and ground planes bonded together. This layered composite structure provides both mechanical strength and electrical function, leveraging the properties of different materials (substrate, conductor, ground layer) to achieve structural integrity at lower cost than monolithic machined parts
3Reliability
If conventional cylindrical structure is used, then traditional design requirements are met, but operation bandwidth is limited
Solution Approach 1:
The patent enables bandwidth tuning by modifying geometric parameters of the planar structure, specifically the line width of the first common ground portion. By adjusting this dimension, the electrical characteristics and impedance matching of the balun can be optimized for different frequency ranges, allowing the same basic structure to adapt to various bandwidth requirements without changing the fundamental design
Data Source
AI summary
A balun is provided. The balun includes a first substrate, a feed conductor, a second substrate, a first ground layer, a second ground layer and a common ground element. The feed conductor includes a feed portion and an extended feed portion. The feed conductor is disposed on the first substrate. The first ground layer is disposed on the second substrate corresponding to the feed portion. The second ground layer is disposed on the second substrate corresponding to the extended feed portion. A gap is formed between the first and second ground layers. The common ground element is disposed on the second substrate. The common ground element is electrically connected to the first and second ground layers. The common ground element includes a first common ground portion parallel and corresponding to the feed conductor.