Close-Spaced Antenna Pair with Half-Wave Decoupling Branch
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Solution Overview
Problem
In terminal devices with multiple antennas operating in the same frequency band, signal coupling and low isolation lead to reduced communication performance due to close proximity, and the distance required for isolation results in increased insertion loss with the Wi-Fi chip.
Innovation Solution
An antenna combination system with a first and second antenna, where the distance between them is less than a threshold, utilizing a first radiation branch with a specific length and phase difference for signal cancellation, and incorporating matching circuits for impedance tuning and phase adjustment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the distance between two antennas is set far away to form physical isolation, then the degree of isolation between antennas is improved, but the insertion loss between the antenna and Wi-Fi chip increases
Solution Approach 1:
The patent utilizes the signal coupling effect that was previously harmful to achieve beneficial decoupling. By designing the first radiation branch with a length of odd multiple of half-wavelengths, the signal coupled from the second antenna undergoes phase inversion and cancels out the original coupled signal, converting the harmful coupling into a useful decoupling mechanism.
Solution Approach 2:
The patent changes the physical parameter of the first radiation branch length to be an odd multiple of half-wavelengths (λ/2, 3λ/2, 5λ/2, etc.). This parameter change causes the coupled signal to undergo phase inversion, enabling signal cancellation and improving isolation without requiring large physical distance between antennas.
2Volume of moving object
If the distance between two antennas is set close to reduce device size, then the device compactness is improved, but the degree of isolation between antennas deteriorates
Solution Approach 1:
The patent transforms the harmful signal coupling caused by close antenna placement into a beneficial decoupling mechanism. The first radiation branch is designed with specific length (odd multiple of half-wavelengths) to invert the phase of coupled signals, causing them to cancel out and achieve isolation even when antennas are placed close together.
Solution Approach 2:
By changing the length parameter of the first radiation branch to specific values (odd multiples of half-wavelengths), the patent enables effective isolation between antennas at close distances, thus reducing device size while maintaining signal isolation performance.
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 system enhances isolation between antennas, reduces mutual interference, and maintains close proximity to the Wi-Fi chip, thereby improving antenna performance and data throughput.
Implementation Method 1
a length of the first radiation branch is an odd multiple of (1/2)λ... a first signal and a second signal having a phase difference of (180±X)° are coupled from the second antenna to the first antenna. Due to the phase difference of (180±X)° between the first signal and the second signal, the first signal and the second signal can cancel each other
Data Source
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AI summary
Embodiments of this application are applicable to the field of antenna technologies, and provide an antenna combination system and a terminal device. The antenna combination system includes a first antenna and a second antenna having a distance less than a first preset threshold. The first antenna includes a first radiation branch and a first feed point, a feed point of the second antenna is arranged on a side away from the first feed point, and a side of the first radiation branch away from the first feed point is grounded. The first feed point is arranged on a side close to the second antenna, and the length of the first radiation branch is an odd multiple of (½)λ. In a case that the second antenna transmits a signal in a first frequency band, a first signal and a second signal that cancel each other are coupled from the second antenna to the first antenna. In other words, in a case that the distance between the first antenna and the second antenna is relatively small, mutual interference between signals of the first antenna and the second antenna in the first frequency band can be reduced by using the antenna combination system provided in this embodiment of this application, thereby increasing the degree of isolation between the first antenna and the second antenna.