Diagonally-Driven Antenna System for Low Correlation
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Solution Overview
Problem
Implementing diversity antenna systems in small wireless communication devices is challenging due to half-wavelengths often being larger than the device housing, and achieving simultaneous high radiation efficiency and low correlation between antennas is difficult, especially in multi-frequency band environments.
Innovation Solution
A diagonally-driven antenna system with two antennas oriented in a saltire configuration across a ground plane, where antenna elements are positioned at the corners and driven out-of-phase at low-band frequencies and optionally in-phase or out-of-phase at high-band frequencies, promoting broad operating frequency bandwidth, high radiation efficiency, and low correlation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If two diversity antennas are placed in close proximity in a small wireless device, then the device size is reduced, but achieving sufficient de-correlation between antennas becomes difficult
Solution Approach 1:
The patent employs asymmetric antenna orientations where the first antenna is positioned along a major axis and the second antenna is positioned along a minor axis at approximately right angles to the first antenna. This asymmetric orthogonal arrangement maximizes spatial de-correlation between the antennas while maintaining a compact form factor, directly resolving the contradiction between reduced device size and sufficient antenna de-correlation.
2Ease of manufacture
If antennas are positioned along major or minor axes for compact layout, then device integration is improved, but radiation efficiency and de-correlation goals become difficult to achieve simultaneously
Solution Approach 1:
The patent implements different orientation configurations for different antenna elements: the first antenna element is oriented along the major axis while the second antenna element is oriented along the minor axis. This local differentiation in orientation quality allows each antenna to maintain optimal radiation characteristics while achieving sufficient de-correlation, resolving the contradiction between ease of manufacture and radiation performance.
Solution Approach 2:
The patent transitions from one-dimensional linear antenna arrangements to two-dimensional orthogonal arrangements by positioning antennas along both major and minor axes. This dimensional change enables simultaneous achievement of compact integration and high de-correlation by utilizing spatial separation in multiple directions rather than simply extending in one direction.
3Reliability
If antenna elements are placed at corners in a diagonally-driven configuration, then low correlation is achieved, but complex driving schemes are required for multi-frequency bands
Solution Approach 1:
The patent implements dynamic phase switching capability where the driving phase between antenna elements can be changed based on operating frequency band. At low-band frequencies, adjacent corner elements are driven out-of-phase to achieve low correlation, while at high-band frequencies, the phase relationship can be switched. This dynamic adaptability maintains low correlation across multiple frequency bands without requiring completely different antenna structures for each band.
Solution Approach 2:
The diagonally-driven antenna system is designed to serve multiple frequency bands with a single unified structure. The same four corner-mounted antenna elements can be driven in different phase configurations to support both low-band and high-band operations, making the antenna system universal across multiple frequency bands rather than requiring separate dedicated antennas for each band.
Data Source
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AI summary
An electronic device (100) includes an antenna system (150) having two antennas (110, 120). A first antenna (110) has a first antenna element (111) positioned near a first corner (191) of a planar, rectangular ground plane (165) and a second antenna element (115) positioned near a second corner of the ground plane that is diagonally across from the first corner. A second antenna (120) has a third antenna element (121) positioned near a third corner (193) of the ground plane that is adjacent to the first corner and a fourth antenna element (125) positioned near a fourth corner (195) of the ground plane that is diagonally across from the third corner. At low-band frequencies, the antenna elements (111, 115) of the first antenna (110) are driven out-of-phase relative to each other. Similarly, at low-band frequencies, the antenna elements (121, 125) of the second antenna (120) are driven out-of-phase relative to each other.