Hyperbolic Microstrip Balun Matching for Low-Profile UWB Arrays
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Solution Overview
Problem
Existing ultra-wideband array antenna designs face challenges in achieving impedance matching due to mutual coupling between elements, leading to deteriorated wideband characteristics, and existing impedance matching methods are complex, costly, and unsuitable for low-profile designs, especially with narrowband and lumped circuit limitations.
Innovation Solution
The method involves integrating a hyperbolic microstrip balun in series with an open circuit line, directly coupling the open circuit line to the radiator layer, and using the array element arm as ground, allowing for impedance transformation and balance-nonbalance conversion without additional dielectric layers, thus keeping the design compact and cost-effective.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If commercial passive baluns are used for impedance matching, then bandwidth is improved, but weight and cost increase
Solution Approach 1:
The patent extracts the essential function of the balun (balance-to-unbalance conversion and impedance transformation) and implements it using a simplified transmission line structure with specific impedance transformation ratios, eliminating the need for heavy commercial passive baluns while maintaining the required bandwidth performance
Solution Approach 2:
The patent changes the impedance parameters by using transmission lines with specific characteristic impedances (e.g., 70.7Ω, 50Ω, 35.4Ω) to achieve the required impedance transformation ratio, replacing heavy balun components with lightweight transmission line structures that provide the same electrical function
2Adaptability or versatility
If complex multilayer structures with multiple via holes are used, then bandwidth is improved, but manufacturing complexity increases
Solution Approach 1:
The patent segments the impedance matching function into multiple transmission line sections with different characteristic impedances, where each section performs a specific transformation step, making the overall complex impedance transformation achievable through simple sequential connections rather than complex multilayer structures
Solution Approach 2:
The patent resolves the manufacturing complexity issue by implementing the impedance transformation in the electrical dimension (through impedance ratios and transmission line lengths) rather than relying on physical multilayer structures, achieving broadband performance through electrical design rather than structural complexity
3Adaptability or versatility
If heavy external baluns and 180-degree mixers are added, then bandwidth is maximized, but overall size and cost increase
Solution Approach 1:
The patent merges the balun function and impedance transformation function into a single integrated transmission line structure, eliminating the need for separate external baluns and 180-degree mixers, thereby reducing overall antenna size while achieving the required bandwidth through the combined impedance transformation ratio of the transmission line sections
4Device complexity
If narrowband and lumped circuit methods are used, then circuit simplicity is maintained, but they are unsuitable for broadband impedance matching
Solution Approach 1:
The patent uses distributed transmission line structures instead of lumped circuit elements, allowing the impedance transformation to be frequency-dependent in a controlled manner, which enables broadband operation while maintaining relatively simple circuit topology through the use of transmission line sections with specific impedance ratios
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
This approach simplifies the matching circuit, reduces processing complexity and material costs, and achieves broadband impedance matching with flexible open circuit line selection, enabling efficient impedance transformation across a wide frequency range.
Implementation Method 1
the hyperbolic microstrip balun can achieve a balance-nonbalance conversion while achieving an impedance transformation
Implementation Method 2
The hyperbolic microstrip balun may realize the impedance transformation between any two impedances
Implementation Method 3
connecting an arm of a balanced end of the hyperbolic microstrip balun in series with the open circuit line, directly coupling the open circuit line to the radiator layer
Data Source
AI summary
An impedance matching method for a low-profile ultra-wideband array antenna is provided. The method includes: connecting an arm of a balanced end of a hyperbolic microstrip balun in series with an open circuit line; directly coupling the open circuit line to a radiator layer; connecting another arm of the balanced end of the hyperbolic microstrip balun to the radiator layer via a metallized via hole, and welding an unbalanced end of the hyperbolic microstrip balun to a coaxial line, so that the coaxial line feeds a power to the antenna via the hyperbolic microstrip balun. In this method, the open circuit line is integrated between the hyperbolic microstrip balun and the radiator layer of the antenna to achieve an impedance matching of the ultra-wideband antenna and to simplify a structure of a matching circuit.