2-Channel Diplexer Microstrip Lines Isolation
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Solution Overview
Problem
Existing diplexers used in dual-band communication terminals face issues with high insertion loss, low isolation, and durability due to their chip-based configuration, which leads to coupling phenomena and limited downsizing potential.
Innovation Solution
A 2-channel diplexer structure is designed with five microstrip lines arranged on a substrate, where the lengths and widths of specific microstrip lines are optimized to achieve improved transmission characteristics by adjusting interline intervals and matching input/output loads, enhancing isolation and reducing size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a chip-based diplexer configuration is used, then integration and compactness are improved, but coupling phenomena occur leading to reduced isolation and increased insertion loss
Solution Approach 1:
The diplexer is divided into multiple independent microstrip lines (first through fifth microstrip lines) with specific configurations. The first and third microstrip lines form a composite structure, while the second and fourth microstrip lines are individual structures. This segmentation allows each line to be optimized independently, reducing coupling effects while maintaining compact overall size.
Solution Approach 2:
Different microstrip lines are assigned different functions and configurations tailored to their specific roles. The first microstrip line handles lower frequency signals with specific width and length parameters, while the third microstrip line handles higher frequency signals with different parameters. This local optimization minimizes interference between channels.
2Area of stationary object
If microstrip line widths and intervals are reduced for miniaturization, then device size is reduced, but transmission characteristics and isolation performance deteriorate
Solution Approach 1:
Specific parameter ranges are established for microstrip line widths (W1-W5) and lengths (L1-L5) to optimize both size and performance. The widths are configured within 0.5-2.0mm and lengths within 10-30mm ranges, with specific relationships between parameters (e.g., L2 > L1, L4 > L3) to maintain transmission characteristics while enabling miniaturization.
Solution Approach 2:
The diplexer utilizes the substrate thickness dimension (H) as an additional degree of freedom for optimization. By controlling the substrate thickness within 0.5-2.0mm and configuring the microstrip lines in a multi-layer arrangement with specific spacing, the design achieves size reduction in the planar dimensions while maintaining performance through vertical dimension optimization.
3Ease of manufacture
If chip-based diplexer is used, then integration is improved, but heat dissipation becomes problematic reducing durability
Solution Approach 1:
The diplexer design extracts the microstrip lines from a fully integrated chip structure and implements them as discrete conductive patterns on a substrate. This extraction allows for better thermal management by distributing heat generation across a larger area and providing direct thermal pathways to the substrate, which acts as a heat sink, thereby improving durability while maintaining integration.
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 optimized diplexer configuration significantly improves isolation and reduces insertion loss, while allowing for miniaturization and increased durability by adjusting the lengths of microstrip lines, thereby enhancing performance and reducing heat-related damage.
Implementation Method 1
five microstrip lines are arranged on the top of the substrate to be parallel to each other with a predetermined interval wherein a front end of a first microstrip line and a front end of a third microstrip line are connected through a first connection line
Implementation Method 2
a 2-channel diplexer structure with two channels in which a substrate having a predetermined size is configured, five microstrip lines are arranged on the top of the substrate to be parallel to each other with a predetermined interval
Data Source
AI summary
The present invention relates to a structure of a diplexer that prevents outputs of both signals from influencing each other by removing mutual interference between both signals when a signal having a high pulse frequency and a signal having a low pulse frequency are combined and radiated by using the same antenna, and more particularly, to a 2-channel diplexer structure with two channels in which a substrate having a predetermined size is configured, five microstrip lines are arranged on the top of the substrate to be parallel to each other with a predetermined interval.