Antenna Isolation in Multi-Layer PCB via Ground Via Segmentation
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Solution Overview
Problem
Conventional multiple antenna communication apparatuses face challenges in maintaining adequate isolation and radiant efficiency due to reduced distance between antennas, which is exacerbated by the demand for smaller consumer electronic devices, leading to increased coupling effects and reduced board area constraints.
Innovation Solution
The solution involves reducing the number of ground vias between antennas to lengthen the current path, thereby reducing the coupling effect caused by feedback ground current, and improving isolation and radiant efficiency without increasing the printed circuit board area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the distance between antennas is reduced to meet smaller device requirements, then the device size is reduced, but the isolation degree between antennas deteriorates
Solution Approach 1:
The patent utilizes the third dimension (vertical stacking) by disposing antenna devices on different layers of a printed circuit board. The first antenna device is on the first layer and the second antenna device is on the fourth layer, with ground vias penetrating through intermediate layers to provide grounding. This vertical arrangement maintains adequate isolation between antennas while reducing the horizontal footprint of the device.
2Reliability
If ground vias are reduced between antennas, then the current path is lengthened and coupling effect is reduced, but the ground voltage distribution may be affected
Solution Approach 1:
The patent segments the grounding structure by providing separate grounding paths for each antenna device through dedicated ground vias. The first antenna device has ground vias connecting to ground terminals on the ground layer, and the second antenna device has separate ground vias connecting to ground terminals. This segmentation isolates the ground current paths of different antennas, reducing mutual coupling while maintaining stable ground voltage distribution.
3Device complexity
If antennas are disposed on the same layer, then the layout is simpler, but the isolation degree between antennas deteriorates
Solution Approach 1:
The patent transitions from a two-dimensional planar arrangement to a three-dimensional layered arrangement. Antenna devices are disposed on different layers (first layer and fourth layer) of the printed circuit board, with ground vias penetrating through the intermediate second and third layers. This vertical separation significantly improves isolation between antennas while the overall structure remains integrated within a compact multi-layer board configuration.
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 approach significantly enhances the isolation degree and radiant efficiency of antennas, meeting design requirements for smaller devices like USB devices while maintaining performance comparable to larger systems.
Implementation Method 1
MIMO wireless communication apparatuses utilize multiple antennas for transmitting and receiving electromagnetic waves. Exhibiting spatial diversity, MIMO wireless communication apparatuses have higher throughput and longer transmission distance than traditional wireless communication apparatuses
Implementation Method 2
the current path between the first antenna device 120 and the second antenna device 130 starts from a ground terminal of the first antenna device 120, passes through a main ground via 140 on the antenna region of the second layer of the printed circuit board 110, further passes through a main ground via 140 on the antenna region of the third layer of the printed circuit board 110, and ends at a ground terminal of the second antenna device 130
Data Source
AI summary
A multiple antenna communication apparatus includes a printed circuit board having multiple layers and two antenna devices. The two antenna devices are disposed on antenna regions of the printed circuit board, and each antenna device comprises a ground terminal. Each ground terminal is coupled to a conductor on a different layer of the printed circuit board. The antenna regions on which the two antenna devices are disposed do not contain any main ground via.