Slot-fed Current Sheet Array Antenna Design
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Solution Overview
Problem
Conventional current sheet arrays suffer from reduced effective bandwidth due to the presence of a non-radiating common mode, which complicates manufacturing and increases depth, making them difficult to integrate with complex feed networks and limiting their applicability in conformal applications.
Innovation Solution
A slot-coupled feed system is used to eliminate the common mode by exciting a fixed slot mode that couples to the current sheet array, forming two radiating modes without shifting the resonant band, allowing for a thin, easily manufactured, and curvable antenna design that maintains wideband performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If additional vias are used to move resonant and common modes above the dipole mode, then wideband performance is achieved, but high band grating lobes occur and the antenna is no longer electrically small
Solution Approach 1:
The patent extracts and eliminates the common mode from the current sheet array system by using a slot-fed configuration. The slot geometry and orientation are specifically designed to suppress the common mode while maintaining the desired radiating modes, thereby achieving wideband performance without the harmful grating lobes that result from conventional mode-shifting approaches
2Reliability
If BALUN-fed current sheet arrays are used to remove the common mode, then wideband performance is achieved, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent removes the BALUN component entirely from the system by using a direct slot-fed configuration. The slot itself serves as the feeding mechanism that inherently suppresses the common mode, eliminating the need for complex BALUN circuitry and associated manufacturing difficulties while maintaining wideband performance
Solution Approach 2:
The slot in the patent serves multiple functions simultaneously: it acts as the feeding mechanism for the current sheet array, provides common mode suppression, and enables wideband operation. This multi-functionality replaces the need for separate BALUN components and simplifies the overall device structure
3Reliability
If BALUN-fed current sheet arrays are used to remove the common mode, then wideband performance is achieved, but the depth of the current sheet array increases
Solution Approach 1:
The patent eliminates the common mode through the slot-fed configuration without requiring the additional depth that BALUN structures would impose. The slot geometry provides common mode suppression in a planar or low-profile configuration, maintaining the electrical smallness of the antenna while achieving wideband performance
4Reliability
If shorting posts are used to reduce electrical length of resonant and common mode loops, then wideband performance is achieved, but the antenna is no longer electrically small
Solution Approach 1:
The patent removes the common mode through slot-fed configuration, which allows the resonant mode to be connected to the dipole mode without requiring shorting posts. This approach maintains the electrical smallness of the antenna by avoiding the need to shift the resonant band, achieving wideband performance while keeping the antenna electrically small
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 enables a continuous wideband performance without the non-radiating common mode, reducing the antenna's thickness and complexity, making it suitable for conformal applications and easier integration with feed networks while maintaining electrical smallness.
Implementation Method 1
The stripline feed excites a mode in a fixed slot which couples to elements of the current sheet array
Implementation Method 2
Because the electric field in the slot is perpendicular to the current sheet array, a common mode cannot exist
Data Source
AI summary
Systems and methods for providing a broadband antenna are described. The systems and methods involved providing a current sheet array. The current sheet array comprises a plurality of unit cells coupled together. Each unit cell comprises a slot and a stripline feed. The stripline feed couples to a dipole array through the slot. An electric field in the slot of a first unit cell is perpendicular to one or more of the stripline feed of the first unit cell and one or more dipoles of the first unit cell.