Meander Pattern Diversity Antennas for 700 MHz Isolation
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Solution Overview
Problem
Designing compact mobile terminals with multiple antennas for low frequency bands, such as the 700 MHz range, poses challenges in achieving high antenna isolation and low correlation, which are essential for efficient operation in limited internal space.
Innovation Solution
A diversity antenna system is implemented using a single planar dielectric substrate with multiple antennas configured in a meander pattern, each with a separate feed port, and oriented in orthogonal directions to reduce coupling and enhance polarization diversity, allowing for efficient operation in the 700 MHz frequency band.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple antennas are designed for low frequency bands (700 MHz range), then antenna isolation and correlation reduction are improved, but device size and internal space requirements increase
Solution Approach 1:
The patent implements nested antennas where inner antennas are positioned within the structure of outer antennas. Specifically, the first antenna element is nested within the second antenna element, and the third antenna element is nested within the fourth antenna element. This nesting arrangement allows multiple antennas to occupy overlapping spatial volumes, achieving high isolation and low correlation in compact low-frequency bands while minimizing the overall device footprint.
Solution Approach 2:
The patent utilizes three-dimensional spatial arrangement by positioning antennas at different depths and orientations within the device housing. The nested configuration extends antennas along the Z-axis (depth dimension) rather than only in the XY-plane, enabling efficient use of internal space. Feed ports are positioned at different locations including side walls and bottom surfaces, creating isolation through spatial separation in multiple dimensions while maintaining compact external dimensions.
2Volume of moving object
If multiple antennas are arranged in compact space, then device compactness is improved, but antenna coupling and correlation increase
Solution Approach 1:
The patent employs asymmetric antenna configurations where antenna elements have different geometries, orientations, and positions. The first and second antenna elements differ in shape and orientation, as do the third and fourth elements. This asymmetry prevents symmetric coupling patterns and reduces mutual coupling effects. Feed ports are positioned asymmetrically at different locations on the housing, further reducing correlation between antenna channels while maintaining compact form factor.
3Volume of stationary object
If antenna elements are positioned close together, then internal space utilization is improved, but signal interference and fading increase
Solution Approach 1:
The patent divides the antenna system into multiple independent antenna elements (first, second, third, and fourth elements) with separate feed ports and independent transmission lines. This segmentation allows each element to be optimized for specific spatial positions and orientations, creating diverse signal paths that reduce fading through spatial diversity. The segmented nested structure enables close positioning while maintaining electrical isolation through separate feeding networks and orthogonal polarizations.
Data Source
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AI summary
A diversity antenna system that operates within a low frequency band ranging from 700 Megahertz is disclosed. A plurality of antennas are folded onto a single printed circuit in a meander pattern configuration. Each antenna has an independent feed port and ground pin. The plurality of antennas are configured within a compact mobile phone space to produce a high isolation and low correlation at resonating frequencies within the 700 Megahertz frequency band.