Compensation Circuit Mitigates Antenna Coupling
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Solution Overview
Problem
Antenna-to-antenna coupling in mobile terminals leads to reduced radiation efficiency due to effective impedance between closely located antennas, complicating communication across different frequency bands and bandwidths.
Innovation Solution
A compensation circuit is introduced, featuring negatively coupled inductors and shunt acoustic resonators between antenna ports, presenting negative capacitance to mitigate coupling effects, with optional additional capacitors and tunable capacitance for frequency range adjustment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple antennas are placed close together in mobile terminals, then communication across different frequency bands and bandwidths is enabled, but antenna-to-antenna coupling occurs which reduces radiation efficiency
Solution Approach 1:
A compensation circuit is introduced as an intermediary element between the coupled antennas. The circuit includes negatively coupled inductors and shunt acoustic resonators that present a negative capacitance to counteract the positive coupling capacitance between antennas, thereby reducing the harmful coupling effect while maintaining close antenna placement for multi-band communication
Solution Approach 2:
The compensation circuit changes the electrical parameters between antenna ports by presenting a negative capacitance that varies with frequency. This parameter change counteracts the coupling capacitance and allows the system to maintain good impedance matching and radiation efficiency across different frequency bands despite close antenna spacing
2Volume of moving object
If antennas are placed close together to reduce device size, then mobile terminal compactness is improved, but antenna-to-antenna coupling increases reducing effectiveness
Solution Approach 1:
The compensation circuit serves as a mediator that enables compact antenna placement by eliminating the harmful coupling effects. The negatively coupled inductors and shunt acoustic resonators create a negative capacitance that cancels the positive coupling capacitance, allowing antennas to be placed close together without sacrificing reliability or effectiveness
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 compensation circuit effectively reduces antenna-to-antenna coupling, enhancing radiation efficiency and maintaining performance across multiple frequency bands by providing negative capacitance to counteract coupling capacitance, thereby improving communication efficiency.
Implementation Method 1
the compensation circuit presents a negative capacitance between the first antenna port and the second antenna port over the first frequency range to reduce the effects of the antenna-antenna coupling
Implementation Method 2
The compensation circuit includes negatively coupled first and second inductors, which are coupled in series between the first antenna port and the second antenna port
Data Source
AI summary
A compensation circuit reduces the negative effects of antenna-to-antenna coupling between proximately located antennas. The compensation circuit is coupled between first and second antenna ports. A first transmit/receive path extends from radio frequency (RF) circuitry to the first antenna port. A second transmit/receive path extends from the RF circuitry to the second antenna port. Antennas are coupled to each of the antenna ports. The compensation circuit includes negatively coupled first and second inductors, which are coupled in series between the first antenna port and the second antenna port. At least one shunt acoustic resonator is coupled between a fixed voltage node and a common node between the first and second inductors. In operation, the compensation circuit presents a negative capacitance between the first antenna port and the second antenna port over the first frequency range to reduce the effects of the antenna-antenna coupling.