Distributed Antenna System Phase Shifting for Hand Loading
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Solution Overview
Problem
Existing antenna systems for wireless devices face challenges in achieving a wide bandwidth while minimizing hand loading effects, which degrade performance due to the trade-off between antenna size and bandwidth, and are sensitive to human body influence.
Innovation Solution
A distributed antenna system comprising multiple small antenna elements connected through a common input/output port with phase shifting elements to minimize reflection coefficients and enhance performance, allowing for a wide bandwidth while reducing hand loading effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If a large antenna element is used to achieve wide bandwidth, then the bandwidth increases, but hand loading effects increase and sensitivity to human body influence increases
Solution Approach 1:
The patent divides a single large antenna element into multiple smaller antenna elements distributed across the device housing. This segmentation allows the system to achieve wide bandwidth through the combined radiation of multiple elements while reducing hand loading effects because the hand cannot simultaneously contact all distributed elements with high current regions.
2Object-affected harmful factors
If the antenna size is reduced to minimize hand loading effects, then hand loading sensitivity decreases, but bandwidth and gain are degraded
Solution Approach 1:
The patent combines multiple small antenna elements into a distributed antenna system that functions as a unified wideband antenna. Through coherent combining of signals from multiple elements, the system achieves bandwidth and gain comparable to or exceeding that of a single large antenna, while the distributed geometry minimizes hand loading effects.
3Duration of action of moving object
If an antenna system relies on ground-plane radiating efficiency for wide bandwidth, then bandwidth increases, but sensitivity to hand loading effects increases
Solution Approach 1:
The patent assigns different functional roles to different parts of the antenna system. The distributed antenna elements are designed to provide the primary radiating function with localized high currents, while the ground plane serves mainly as a reference potential and support structure rather than the primary radiating element. This local quality differentiation reduces hand loading sensitivity.
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
The solution achieves a wide bandwidth with reduced sensitivity to hand loading, maintaining a small size and effective electromagnetic volume, thereby improving the antenna's performance and radiation efficiency.
Implementation Method 1
at least one phase shifting element, such as a for instance a transmission line (micro coaxial cable, microstrip, stripline or coplanar transmission line, to name a few examples), a reactive network (based on inductors and capacitors), an active phase shifter (based on a combination of diodes and/or transistors) or a combination of them, placed between at least one of said driven points and the combining structure of the system
Data Source
AI summary
A wireless handheld device comprises an internal antenna system that operates in first and second non-overlapping frequency bands with respective bandwidths. The antenna system includes: a ground plane; first and second antenna elements connected to a common input/output port, wherein a bandwidth of each of the antenna elements is less than at least one of the first and second operating frequency bandwidths and less than a frequency bandwidth for the antenna system; a combining structure to couple first and second signal transmission paths from the antenna elements to the common input/output port; and a phase shifting element on the first signal transmission path that imparts a phase delay to signals on the first signal transmission path. The phase delay minimizes a sum of reflection coefficients of the antenna elements to cause the frequency bandwidth for the antenna system to include at least the first and second operating frequency bands.