Compact Broadband Balun Layout Using Shared Coupled Delay Lines
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Solution Overview
Problem
Existing broadband balun structures become less effective at higher frequencies due to reduced coupling, leading to increased loss and impracticality in compact designs for test and measurement applications.
Innovation Solution
The implementation of coupled-triple delay lines in balun structures, which share a common delay segment and reduce layout spacing, allowing for a more compact and lower-loss design by eliminating unnecessary intentional delay segments and interconnect length, while maintaining effective impedance matching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If traditional broadband balun structures are used, then impedance matching is achieved, but the structure becomes large and lossy at higher frequencies
Solution Approach 1:
The patent combines multiple delay lines into a shared common delay section. Specifically, the first and second coupled delay lines share a common delay line, and the third and fourth coupled delay lines share another common delay line. This merging reduces the total number of separate delay segments and interconnects, resulting in a more compact structure with reduced signal loss at higher frequencies.
Solution Approach 2:
The patent transitions from a planar layout to a three-dimensional stacked architecture by placing delay lines on different layers of a substrate. The coupled delay lines are positioned on different layers with vertical interconnects, allowing the balun to achieve compactness in the vertical dimension while maintaining the required electrical performance and reducing signal loss.
2Adaptability or versatility
If more intentional delay segments are added to improve impedance matching, then bandwidth is improved, but the layout spacing increases and compactness is reduced
Solution Approach 1:
The patent merges adjacent coupled delay lines by sharing common delay segments. The first and second coupled delay lines share a common delay line, as do the third and fourth coupled delay lines. This consolidation maintains the required bandwidth coverage through proper phase shifting while reducing the overall layout spacing and eliminating redundant interconnects.
Solution Approach 2:
The patent utilizes vertical stacking of delay lines on different substrate layers to achieve compact layout. By positioning delay lines in the vertical dimension rather than spreading them out horizontally, the design maintains adequate bandwidth coverage through multiple delay segments while significantly reducing the planar layout spacing.
3Reliability
If thin interconnect lines are used to separate delay lines, then coupling is reduced, but additional delay is introduced
Solution Approach 1:
The patent positions coupled delay lines on different layers of the substrate and uses vertical interconnects to connect them. This three-dimensional arrangement provides effective coupling isolation between adjacent delay lines while minimizing the length of interconnect paths, thereby reducing the additional signal delay that would otherwise be introduced by longer horizontal routing.
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 compact balun design achieves a 2 dB gain boost at the design frequency and improved phase response, making it suitable for a wide range of applications from PCBs at 1 GHz to ASICs at 60 GHz, with reduced precursor errors from impedance mismatch.
Implementation Method 1
the first transmission line positioned to allow coupling of a first portion of the first transmission line simultaneously to both a second portion of the first transmission line and a portion of the second transmission line
Data Source
AI summary
A broadband balun structure has a single-ended port, a balanced port, a first transmission line connected between the single-ended port and one side of the balanced port, and a second transmission line connected to the other side of the balanced port, the first transmission line positioned to allow coupling of a first portion of the first transmission line simultaneously to both a second portion of the first transmission line and a portion of the second transmission line. A broadband balun structure includes a 180° hybrid using coupled-line structures, and a phase-shift network using coupled-line structures, the coupled-line structures positioned to couple at least one line section simultaneously to two other line sections. A test and measurement system and a test and measurement instrument, and at least one balun structure.