Co-located Complementary Antenna Pairs for High Isolation
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Solution Overview
Problem
In-band full-duplex wireless communication systems face significant challenges due to self-interference, particularly in achieving high isolation between transmission and reception signals, which limits data throughput and is exacerbated by the size and complexity of conventional antenna solutions.
Innovation Solution
The use of co-located complementary antenna pairs with orthogonal linear polarization, such as dipole and slot antennas, arranged in a compact manner to achieve extremely high isolation (60 dB or more) without the need for a circulator, allowing simultaneous transmission and reception in the same frequency band.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional echo cancellation with a single antenna and circulator is used, then in-band full-duplex operation is achieved, but signal leakage occurs due to low isolation level
Solution Approach 1:
The single antenna is segmented into two separate antennas (first and second antennas) with different polarizations. This segmentation allows the system to separate transmission and reception paths more effectively, achieving higher isolation levels and reducing signal leakage while maintaining in-band full-duplex operation.
Solution Approach 2:
Each antenna is assigned a specific polarization characteristic (first antenna with first polarization, second antenna with second polarization). This local quality differentiation enables the system to exploit polarization diversity to achieve high isolation between transmit and receive paths, eliminating signal leakage issues.
2Object-generated harmful factors
If two separate antennas with high isolation are used, then signal leakage is reduced, but device size and complexity increase
Solution Approach 1:
The two antennas with different polarizations are co-located and integrated into a single antenna assembly. This merging approach maintains the high isolation benefits of separate antennas while reducing overall device size and complexity compared to using two completely separate antenna systems.
Solution Approach 2:
The system transitions from spatial separation to polarization separation by utilizing different polarization dimensions (e.g., horizontal and vertical, or circular polarizations). This allows high isolation to be achieved without increasing physical distance between antennas, thereby reducing device size.
3Reliability
If conventional antenna designs are used, then in-band full-duplex operation is possible, but self-interference remains a significant impediment
Solution Approach 1:
The system changes the polarization parameter of the antennas to achieve high isolation between transmit and receive paths. By using orthogonally polarized antennas, the system effectively reduces self-interference while maintaining in-band full-duplex operation.
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 configuration effectively reduces self-interference, enabling compact and efficient in-band full-duplex operation with high isolation, suitable for next-generation wireless communication standards like 5G, while eliminating the need for large and heavy circulators and minimizing space and complexity issues.
Implementation Method 1
co-located complementary antenna pairs with orthogonal linear polarization, such as dipole and slot antennas
Data Source
Figure 1
Figure 2A~2C
Figure 3A~3B
AI summary
Described herein are technologies related to an in-band full-duplex wireless communication operation. More particularly, the technologies utilize a complementary pair of antennas for signal transmission and reception arranged in a new manner to be both compact (relatively to conventional approaches) and provide an extremely high (e.g., 60 dB or more) isolation.