All-Metal Vivaldi Antenna Element With Direct Coax Feed
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Solution Overview
Problem
Vivaldi antenna arrays face limitations in achieving ultra-wideband operation due to mutual coupling and space constraints in array configurations, leading to restricted bandwidth and power-handling issues with printed circuit board designs.
Innovation Solution
An all-metal Vivaldi antenna element with a direct coax feed, eliminating the need for quarter-wave stubs and allowing for a single transition from coax to slot-line, enabling higher bandwidth and power handling without soldering, and featuring a modular design for easy assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a Vivaldi antenna is condensed into an array configuration, then radiation is generated through constructive interference, but the bandwidth is limited to 3:1, 4:1, or occasionally 5:1 due to space constraints for feed circuits
Solution Approach 1:
The patent extracts and eliminates the quarter-wave stub component from the feed circuit design. By removing this band-limiting element, the antenna achieves ultra-wideband operation (10:1 bandwidth) without the spatial and bandwidth constraints that traditionally limited Vivaldi arrays to 3:1, 4:1, or 5:1 bandwidths.
Solution Approach 2:
The patent changes the feed circuit parameters by transitioning from traditional microstrip/strip-line feeds with quarter-wave stubs to an alternative feed configuration that eliminates the stub. This parameter change enables the feed circuit to accommodate ultra-wideband operation while maintaining compact dimensions suitable for array configurations.
2Ease of manufacture
If printed circuit board designs are used for Vivaldi antennas, then manufacturing is inexpensive, but power-handling capability is limited
Solution Approach 1:
The patent employs a composite construction combining aluminum extrusions for the radiating elements with PCB-mounted feed circuits. This composite approach allows the high-power aluminum structure to handle significant power while the PCB provides cost-effective feed circuit implementation, achieving both low manufacturing cost and high power-handling capability.
3Ease of operation
If multiple transitions/transformers are used to feed the antenna from coaxial cable, then connection is enabled, but bandwidth is limited due to band-limited design of each transition
Solution Approach 1:
The patent removes the quarter-wave stub transformer from the feed path. This extraction eliminates a band-limiting component, allowing the antenna to operate across an ultra-wide bandwidth (10:1) while maintaining the necessary coaxial to slot-line transition through a simplified feed structure.
4Ease of operation
If quarter-wave stubs are used for strip-to-slot feed transition, then feeding is enabled, but bandwidth is limited and the design becomes more complex
Solution Approach 1:
The patent extracts and eliminates the quarter-wave stub from the feed transition design. By removing this band-limiting component, the antenna achieves ultra-wideband operation (10:1 bandwidth) while maintaining effective strip-to-slot feed transition through an alternative, simplified feed structure.
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 solution achieves a 12:1 bandwidth with VSWR below 2 across a broad frequency range, supports high-power applications, and allows for modular assembly without soldering, addressing the limitations of traditional Vivaldi arrays.
Implementation Method 1
The antenna guides a wave from transition line impedances (50 Ohms) to free space impedances (377 Ohms) by gradually changing the taper of the slot
Implementation Method 2
The antenna functions to radiate energy over nearly any range of frequencies that can be guided along the slot-line
Data Source
AI summary
An antenna element for fabricating into a linear or planar array includes a tapered slot along a main axis of the antenna element body that extends from a first slot end, defined by an outwardly flared opening at a second end of the antenna element, into a second meandering portion that is offset from the main axis, and then into a second slot end having a bend with respect to the main axis, and finally into a slot-line cavity proximate to the first end of the antenna element body. A feed port extends into the antenna element body from the outer surface of the first end of the antenna element body into the second slot end bend adjacent the slot-line cavity.