Dual-Band PCB Antenna Layout Using Angular Polarization Separation
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Solution Overview
Problem
Conventional dual-band antennas for optical network termination (ONT) devices face significant mutual interference between 2.4G and 5G bands due to their close proximity, which is exacerbated by the need for a smaller size, leading to reduced performance.
Innovation Solution
The design incorporates two antennas printed on a rectangular region of a PCB, oriented at different angles and with stubs that extend in various directions, forming a polarization difference to minimize interference while maintaining a compact size, utilizing baluns to separate feeders and reduce mutual impact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the 2.4G antenna and the 5G antenna are disposed together in a back-to-back manner to achieve a smaller size, then the antenna size is reduced, but the mutual interference between the two antennas increases
Solution Approach 1:
The patent applies asymmetry by disposing the 2.4G antenna and 5G antenna at different angles relative to the long edge of the rectangular region. Specifically, the 2.4G antenna extends in a first direction forming a first angle with the long edge, while the 5G antenna extends in a second direction forming a second angle with the long edge, where the first angle is different from the second angle. This asymmetric angular arrangement creates polarization difference between the two antennas, which effectively reduces mutual interference while maintaining a compact dual-band antenna structure.
2Area of stationary object
If the 2.4G antenna and the 5G antenna are placed close to each other to reduce overall antenna size, then the compactness is improved, but the signal isolation between bands deteriorates
Solution Approach 1:
The patent employs asymmetric angular disposition where the 2.4G antenna and 5G antenna are oriented at different angles (first angle and second angle respectively) relative to the rectangular region's long edge. This asymmetric configuration generates polarization difference between the two antennas, which enhances signal isolation between bands even when the antennas are placed in close proximity within the same rectangular region, thereby maintaining compact area while improving reliability.
3Device complexity
If a single feed point solution is used for both 2.4G and 5G antennas to simplify the structure, then the device complexity is reduced, but the mutual interference between bands increases
Solution Approach 1:
While the patent uses a single feed point solution for both antennas (maintaining low device complexity), it compensates for the potential increase in mutual interference by implementing asymmetric angular disposition. The 2.4G antenna and 5G antenna are oriented at different angles relative to the rectangular region, creating polarization difference that reduces band interference despite the simplified single feed structure.
Data Source
AI summary
An antenna includes a first antenna having a first feeding portion and at least one stub, and a second antenna having a second feeding portion and at least one stub. The first feeding portion is disposed on a first side of a first diagonal line of the rectangular region. The at least one stub of the first antenna extends from the first feeding portion in a first direction. A first angle is between the first direction and a long-edge direction of the rectangular region. The second feeding portion is disposed on a second side of the first diagonal line of the rectangular region. The at least one stub of the second antenna extends from the second feeding portion in a second direction. A second angle is between the second direction and the long-edge direction of the rectangular region and is different from the first angle.