Plug-In Waveguide Filter Structure for Low-Loss Antenna Arrays
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Solution Overview
Problem
Existing antenna arrays face challenges in implementing high Q-factor filters with low insertion loss and strong frequency suppression due to the low Q-factor of microstrip or slot resonators, which increases the cost and complexity of integration, especially when trying to fit separate filters onto circuit boards with antennas and active circuits on opposite sides.
Innovation Solution
A waveguide section with air-filled conducting tubes and plug-in filter devices featuring electrically conducting elements spaced apart by a dielectric holding arrangement, allowing for electromagnetic coupling and easy integration with antenna arrays, reducing insertion loss and simplifying assembly by eliminating irises and using dielectric connecting members.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If microstrip or slot resonators are used to construct filters for antenna elements, then the filter structure can be integrated with the circuit board, but the Q-factor is low which causes increased insertion loss
Solution Approach 1:
The patent changes the fundamental parameter of the resonator structure from planar microstrip/slot types to three-dimensional waveguide cavities. This dimensional parameter change enables high Q-factor operation while maintaining integrability through the plug-in filter device design that can be mounted on the circuit board.
Solution Approach 2:
The patent introduces a separate plug-in filter device as an intermediary component that bridges the waveguide structure and the circuit board. This mediator allows the high Q-factor waveguide filter to be integrated with the antenna element without directly coupling the microstrip resonators to the waveguide, thereby reducing insertion loss while maintaining ease of manufacture.
2Device complexity
If traditional filters are designed as isolated components, then the filter structure is simple, but the antenna element bandwidth is reduced and suppression characteristic is modified due to interaction with the antenna
Solution Approach 1:
The patent merges the filter device with the antenna element by integrating the plug-in filter directly into the antenna structure. The electrically conducting elements of the filter are positioned to interact with the electromagnetic fields of the antenna, creating a unified system where the filter and antenna work together as a single integrated component rather than separate isolated elements.
Solution Approach 2:
The patent employs adjustable and reconfigurable electrically conducting elements within the filter device that can be dynamically tuned to optimize performance. This dynamic capability allows the filter characteristics to be adjusted to match different operating conditions and antenna configurations, thereby maintaining bandwidth and suppression characteristics without requiring complex fixed structures.
3Ease of manufacture
If separate filters are fitted as SMT-components on circuit boards with antennas and active circuits on opposite sides, then the filter can be separately manufactured, but the integration is difficult due to space constraints
Solution Approach 1:
The patent segments the filter into a separate plug-in module that can be manufactured independently and then installed in the waveguide. This segmentation allows the filter to be produced using standard manufacturing processes while simplifying integration, as the modular plug-in design requires only simple mechanical insertion and connection to the waveguide structure, avoiding complex multi-sided PCB assembly.
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 solution enables a reliable, cost-effective, and uncomplicated filter structure for large waveguide arrays with low insertion loss and flexible manufacturing, integrating filters directly with antennas to enhance performance and reduce production costs.
Implementation Method 1
The electrically conducting elements are arranged to be electromagnetically coupled such that a radio frequency signal passing via a corresponding waveguide conducting tube is arranged to be electromagnetically filtered
Implementation Method 2
Each plug-in filter device is adapted to be retained in the corresponding waveguide conducting tube by means of a dielectric holding arrangement such that the electrically conducting elements are spaced apart from the waveguide conducting tube
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
The present disclosure relates to a waveguide section (1) comprising at least one air-filled waveguide conducting tube (2; 2a, 2b, 2c, 2d, 2e, 2f, 2g, 2h) having an electrically conducting inner wall (3, 3a). Each waveguide conducting tube (2; 2a, 2b, 2c, 2d, 2e, 2f, 2g, 2h) comprises a plug-in filter device (4, 4a, 4b, 4c, 4d, 4e, 4f, 4g, 4h) with two or more electrically conducting elements (5, 6, 7, 8; 5a, 6a, 7a, 8a) arranged in series and spaced apart by a connecting arrangement (11, 11a). Each plug-in filter device (4, 4a, 4b, 4c, 4d, 4e, 4f, 4g, 4h) is adapted to be retained in the corresponding waveguide conducting tube (2; 2a, 2b, 2c, 2d, 2e, 2f, 2g, 2h) by means of dielectric holding arrangement (9, 10; 9a, 10a; 79) such that the electrically conducting elements (5, 6, 7, 8; 5a, 6a, 7a, 8a) are spaced apart from the waveguide conducting tube (2; 2a, 2b, 2c, 2d, 2e, 2f, 2g, 2h). The electrically conducting elements (5, 6, 7, 8; 5a, 6a, 7a, 8a) are arranged to be electromagnetically coupled such that passing a radio frequency is electromagnetically filtered.