Capacitive Antenna Feed Layout for Stable Multi-Band Tuning
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Solution Overview
Problem
Existing antennas in electronic devices face challenges in maintaining radiation performance and frequency shifting without substantial performance degradation, particularly when multiple frequency bands are required, due to leak currents and undesired frequency shifts during low-band switching.
Innovation Solution
The proposed solution involves a structural change in the antenna design, incorporating a conductive portion separated by non-conductive portions, with a variable circuit connected to ground through different electrical paths, allowing indirect feeding to maintain radiation performance across frequency bands.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a switching structure is used to shift frequency bands, then frequency shifting capability is improved, but antenna performance degrades due to leak current
Solution Approach 1:
The patent extracts the harmful leak current effect by introducing a separate cancellation path. The switching structure for frequency shifting is retained, but its harmful side effect (Coff variation) is isolated and cancelled through an additional electrical path that generates an opposing effect, thereby removing the performance degradation while preserving frequency shifting capability.
Solution Approach 2:
The patent introduces an intermediary cancellation path consisting of additional switching elements and reactive components. This intermediary structure mediates between the frequency shifting requirement and the antenna performance maintenance, allowing frequency to be shifted while the intermediary path simultaneously compensates for the harmful effects through controlled reactance changes.
2Device complexity
If multiple frequency bands are implemented in a single antenna, then device integration is improved, but SAR standard compliance and radiation performance deteriorate
Solution Approach 1:
The patent segments the antenna's electrical path into multiple independent switching-controlled sections. Each segment can be independently controlled to optimize performance for specific frequency bands, allowing the single antenna to handle multiple bands while maintaining radiation performance and SAR compliance through selective activation of different path configurations.
Solution Approach 2:
The patent implements dynamic reconfiguration of the antenna's electrical characteristics through switching elements that can change the effective length and reactance of different path sections. This dynamic adjustment allows the antenna to adapt its radiation pattern and impedance matching for each frequency band, preventing SAR violations and maintaining optimal performance across bands.
3Adaptability or versatility
If frequency shifting is performed in low band, then low band adaptability is improved, but mid band and high band frequency stability deteriorate
Solution Approach 1:
The patent introduces a cancellation path as an intermediary mechanism that actively compensates for the harmful effects of low-band frequency shifting. When low-band frequency shifting occurs, the intermediary path generates an opposing reactance change that counteracts the unwanted frequency drift in mid and high bands, thereby maintaining their stability while allowing low-band adaptability.
Solution Approach 2:
The patent applies preliminary anti-action by pre-configuring the cancellation path to produce effects that oppose the harmful consequences of frequency shifting. The switching elements in the cancellation path are arranged to automatically activate and generate counteracting reactance changes before the harmful frequency drift can significantly impact mid and high band performance.
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 frequency shifts in specific frequency bands without degrading overall performance, improving radiation characteristics and maintaining optimal operation across multiple bands.
Implementation Method 1
a wireless communication circuit disposed on the substrate and capacitively coupled to a first point of the conductive portion positioned at a first electrical distance from the at least one non-conductive portion through a first electrical path
Data Source
AI summary
According to various embodiments, an electronic apparatus comprises: a housing comprising at least one conductive portion arranged through at least one non-conductive portion; a substrate arranged in an internal space of the housing and comprising a ground; a wireless communication circuit arranged on the substrate and capacitively coupled to a first point of the at least one conductive portion; the first point being located at a first electric distance from the at least one non-conductive portion, through a first electric path; and a variable circuit arranged on a second electric path branched from the first electric path and connected to the ground, wherein the at least one conductive portion is connected to the ground through a third electric path at a second point further from the at least one non-conductive portion than the first point, and the first electric distance may be shorter than a second electric distance from the first point to the second point.