Folded Multiple-Band Antenna for Mobile Devices
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Solution Overview
Problem
The challenge in cellular device design is to miniaturize multi-functional devices while minimizing signal interference and specific absorption rate (SAR) issues, as well as ensuring hearing aid compatibility, which is difficult with internal antennas due to their proximity to the user's head and potential interference from other components.
Innovation Solution
A multiple-band antenna system is integrated into a mobile wireless communications device, featuring a dielectric substrate with patterned electrically conductive traces forming a primary and secondary radiator, where the radiators are spaced apart and coupled to respective outputs, exploiting characteristic modes to achieve low correlation and reduced interference, allowing for efficient operation across various frequency bands.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If internal antennas are used to reduce device footprint, then device size is reduced, but specific absorption rate (SAR) increases due to proximity to user's head
Solution Approach 1:
The patent transitions from planar 2D antenna layouts to three-dimensional folded and meandered antenna structures. The antenna elements are folded back on themselves and positioned at different heights above the ground plane, creating vertical separation that reduces SAR while maintaining compact horizontal footprint.
Solution Approach 2:
The antenna design nests multiple functional elements within a compact structure. The folded antenna elements are positioned within the device housing volume, with ground planes and radiating elements arranged in layered configurations that maximize space utilization while maintaining electromagnetic performance.
2Adaptability or versatility
If multiple antennas are integrated into compact device, then device functionality increases, but signal interference between antennas increases
Solution Approach 1:
The patent divides the antenna system into spatially separated segments. Multiple antenna elements are positioned at different locations and orientations within the device, with physical separation and angular diversity that reduces mutual coupling and signal interference between adjacent antennas.
Solution Approach 2:
The antenna elements employ asymmetric folded and meandered geometries with different path lengths and configurations. This asymmetry creates different current distributions and radiation patterns that reduce correlation between antennas, improving signal independence for MIMO operations.
3Ease of operation
If internal antennas are used instead of external antennas, then device ergonomics improve, but hearing aid compatibility deteriorates
Solution Approach 1:
The patent uses vertical dimensionality in the antenna design to increase separation between the antenna elements and the user's head. The folded and meandered structures extend in the vertical direction, creating greater distance from the user's ear while maintaining horizontal compactness for ergonomic handheld use.
4Volume of moving object
If antenna elements are placed in close proximity, then device size is reduced, but manufacturing precision requirements increase
Solution Approach 1:
The patent combines multiple antenna elements and ground planes into an integrated printed circuit board structure. The antenna elements are fabricated as conductive traces on the same substrate as other device components, using standard PCB manufacturing processes that provide inherent alignment tolerance and reduce the need for separate precision assembly steps.
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 design enables compact, high-performance MIMO functionality with minimal correlation and gain imbalance, reducing signal interference and SAR concerns, while maintaining device durability and usability.
Implementation Method 1
exploiting characteristic modes to achieve low correlation and reduced interference
Data Source
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AI summary
A mobile wireless communications device (20) may include a housing (22), a wireless transceiver (21) carried by the housing and having a primary output (55), and a secondary output (56), and a multiple-band antenna (23) carried by the housing and coupled to the wireless transceiver. The multiple-band antenna may include a dielectric substrate (24) and a pattern of electrically conductive traces thereon defining a primary radiator (26) and a secondary radiator (25) spaced apart from the primary radiator. The primary radiator may include a first elongate member (32) having a primary feed (27) coupled to the primary output, and a first reference member (33) spaced from the first elongate member and at least partially laterally surrounding the first elongate member and coupled to a reference voltage. The secondary radiator may include a second elongate member having a secondary feed (31) coupled to the secondary output.