Dual Band MIMO Antenna Array With Patterned Nulls
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Solution Overview
Problem
The design of wireless access points with Multiple-Input, Multiple-Output (MIMO) radios faces challenges due to the need for multiple antennas, which complicates physical design and requires efficient antenna arrays that can operate effectively in both the 2.4 GHz and 5 GHz frequency bands while maintaining high isolation between different radio streams.
Innovation Solution
The development of dual-band antenna elements and sub-arrays with specific radiation patterns and configurations that allow for dynamic reconfiguration between omni-directional and sectored modes, enabling efficient use of multiple MIMO radios with high isolation between streams, even when closely spaced, using a patterned conductive layer on a dielectric circuit card with microstrip feed lines and radial stubs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple antennas are used for MIMO radios, then data rates and connection stability are improved, but device complexity and physical design difficulty increase
Solution Approach 1:
The patent combines multiple antenna elements into integrated antenna arrays where multiple radiating elements are merged into a single structural unit. The antenna arrays integrate multiple feed lines and radiating elements working together to provide MIMO functionality while simplifying the overall physical design compared to separate antenna components.
Solution Approach 2:
The antenna arrays are designed to support multiple functions including omnidirectional and sectorized radiation patterns, dual-frequency operation (2.4 GHz and 5 GHz bands), and multiple stream transmission. This multi-functionality allows a single antenna array structure to replace what would otherwise require multiple separate antenna systems.
2Volume of moving object
If antennas are closely spaced to reduce device size, then compactness is improved, but isolation between different radio streams deteriorates
Solution Approach 1:
The patent applies different local characteristics to different regions of the antenna array. Specific antenna elements are configured with distinct radiation patterns (omnidirectional vs. sectorized) and different feed line configurations to create local isolation zones. This allows closely spaced elements to maintain stream isolation through localized pattern differentiation rather than relying solely on physical spacing.
Solution Approach 2:
The antenna array employs dynamic reconfiguration capability where the radiation pattern can be switched between omnidirectional and sectorized modes. This dynamic adjustment allows the system to optimize isolation between streams based on operational requirements, maintaining reliability even when elements are closely spaced for compactness.
3Adaptability or versatility
If dual-band operation is implemented, then versatility is improved, but antenna design complexity increases
Solution Approach 1:
The antenna arrays are designed as universal structures that operate across both 2.4 GHz and 5 GHz frequency bands. The same physical antenna elements and feed line configurations support dual-band operation, eliminating the need for separate antenna systems for each frequency band and thereby reducing overall design complexity despite the versatility gain.
Solution Approach 2:
The patent utilizes parameter changes in the feed line configurations and radiating element dimensions to enable dual-band operation. By carefully designing the electrical parameters (length, width, spacing) of the antenna elements and feed lines, the system achieves resonance at both 2.4 GHz and 5 GHz frequencies using a single unified antenna structure.
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 solution enhances the performance of MIMO radios by ensuring high isolation between different streams, allowing for stable and efficient communication across both frequency bands, even in crowded environments, and supports various configurations to adapt to different communication requirements.
Implementation Method 1
dual-band antenna elements and sub-arrays with specific radiation patterns and configurations that allow for dynamic reconfiguration between omni-directional and sectored modes
Data Source
AI summary
Antenna arrays and access points are disclosed. An antenna array includes first second, third, and fourth antennas formed in a 2×2 grid on a first surface of a planar substrate. Each of the four antennas is linearly polarized in a first direction and provides a roughly cardiod radiation pattern in a plane normal to the first direction. Nulls of the cardiod radiation patterns of the first and second antennas face the third and fourth antennas, respectively, and nulls of the cardiod radiation patterns of the third and fourth antenna face the first and second antennas, respectively.