Aperture Feed Network Common Mode Rejection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Broadband apertures in wireless communication devices are bandwidth limited and suffer from scan anomalies due to in-band common-mode resonances, which affect the performance of feed networks.
Innovation Solution
An aperture feed network design is implemented, featuring a substrate with conductive traces and ground plane structures of irregular shapes, along with striplines resistively coupled to ground, to create a differential signal line that effectively rejects common-mode signals and achieves impedance matching between antennas and RF circuitry.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional feed networks are used, then bandwidth is limited, but increasing bandwidth may introduce common-mode resonances and scan anomalies
Solution Approach 1:
The patent extracts and removes common-mode signals from the differential signal path using dedicated common-mode rejection circuits. These circuits are specifically designed to identify and eliminate common-mode components while preserving differential signal integrity, thereby preventing scan anomalies within the broadband frequency range.
Solution Approach 2:
The feed network employs asymmetric ground plane structures and unequal length control traces to create intentional imbalances that favor differential mode operation. By designing the ground planes with different shapes and positions relative to each trace, the structure inherently suppresses common-mode resonances while maintaining broadband performance.
2Adaptability or versatility
If broadband aperture is used, then frequency range is extended, but common-mode resonances occur within the band
Solution Approach 1:
The patent converts the potentially harmful common-mode resonances into beneficial common-mode rejection. By intentionally designing common-mode rejection circuits that resonate at the same frequencies where common-mode issues occur, the system transforms these resonant frequencies from problems into features that actively suppress common-mode signals while maintaining broadband operation.
Solution Approach 2:
The feed network introduces intermediary common-mode rejection circuits between the antenna aperture and the receiver. These intermediary structures act as filters that allow differential signals to pass through while blocking common-mode resonances, enabling broadband frequency range without the harmful effects of common-mode interference.
3Reliability
If differential signal line is implemented, then common-mode rejection is improved, but impedance matching becomes more complex
Solution Approach 1:
The patent merges the common-mode rejection function with the impedance matching network into a single integrated structure. The same ground plane configurations and trace geometries that provide common-mode rejection also serve as the impedance transformation elements, eliminating the need for separate matching circuits and reducing overall device complexity.
Solution Approach 2:
The feed network structures are designed to perform multiple functions simultaneously: the ground planes provide both common-mode rejection and impedance transformation, while the trace geometries serve as both signal paths and matching elements. This multi-functionality reduces the number of discrete components needed while maintaining effective common-mode rejection.
Data Source
AI summary
An aperture feed network includes a substrate having a first surface and a parallel second surface, first and second conductive traces on the first surface of the substrate, a third conductive trace on the second surface of the substrate, a conductive via extending through a thickness of the substrate, and one or more ground plane structures on the second surface of the substrate. The substrate comprises a dielectric material. The first and second conductive traces together form a differential signal line. The third conductive trace comprises a first branch and a second branch. The conductive via contacts the first branch of the third conductive trace on the second surface of the substrate and the second conductive trace on the first surface of the substrate. The one or more ground plane structures have irregular shapes.