Capacitively Loaded Dipole Antenna for Mobile Low Frequency
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Solution Overview
Problem
Existing mobile device antenna designs are ineffective at low frequencies, such as 200-700 MHz, which are required for modern wireless communication devices that support applications like broadcast television, and struggle with size reduction and performance enhancement due to classical antenna structure limitations.
Innovation Solution
The design incorporates a conductive structure that the user interacts with, which becomes part of the antenna, using capacitive or direct coupling, and includes active control elements like switches or transistors to configure antenna characteristics for low frequency operation and multi-band support, enabling frequency switching and beam management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If classical antenna structures are used, then resonant frequency and bandwidth can be achieved, but the physical volume required increases and device size cannot be reduced
Solution Approach 1:
The patent applies parameter changes by transforming the antenna structure from a traditional resonant design to a capacitively loaded magnetic dipole configuration. This involves changing the electrical parameters through capacitive loading elements that enable the antenna to resonate at low frequencies while maintaining a compact physical size. The capacitive loading fundamentally alters the impedance characteristics and resonant behavior of the antenna structure.
Solution Approach 2:
The patent utilizes dimensionality change by employing a magnetic dipole configuration that operates in a different dimensional regime compared to traditional electric dipoles. The capacitive loading creates a magnetic moment that allows the antenna to function effectively at wavelengths much larger than its physical dimensions, effectively operating in a sub-wavelength regime that overcomes the traditional size-frequency relationship.
2Adaptability or versatility
If multiple resonant antenna structures are used for multi-band applications, then frequency coverage is improved, but device complexity and size increase
Solution Approach 1:
The patent implements universality by designing a single capacitively loaded magnetic dipole antenna structure that can operate across multiple frequency bands. The capacitive loading elements can be configured to provide different resonant frequencies, allowing the same physical structure to serve multiple communication bands (e.g., TV broadcast, cellular, Wi-Fi) without requiring separate antenna elements for each band.
Solution Approach 2:
The patent applies dynamics through electronically controllable capacitive loading elements that can dynamically adjust their capacitance values. This dynamic adjustment capability allows the antenna to be reconfigured for different frequency bands and operating conditions, providing multi-band functionality through a single adaptable structure rather than multiple fixed structures.
3Reliability
If traditional antenna designs are used, then high frequency operation is achieved, but low frequency excitation capability is lost
Solution Approach 1:
The patent applies parameter changes by introducing capacitive loading elements that fundamentally alter the electrical characteristics of the antenna. These capacitive elements increase the effective electrical length of the antenna structure, enabling it to resonate at low frequencies (such as TV broadcast bands) while maintaining a compact physical size suitable for modern mobile devices.
Solution Approach 2:
The patent uses capacitive loading elements as intermediary components that mediate between the physical antenna structure and the desired low-frequency resonant behavior. These capacitive elements act as electrical transformers that allow the compact physical structure to achieve the electrical characteristics necessary for low-frequency operation, effectively bridging the gap between small size and low-frequency resonance.
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 solution allows for efficient low-frequency operation, reduced device size, and improved performance by actively reconfiguring antenna characteristics, supporting multiple frequency bands and enhancing communication capabilities.
Implementation Method 1
The antenna is coupled to the conductive structure such that the conductive structure and user become part of the antenna element when the device is being used. The user can be directly or indirectly coupled to the antenna through the conductive structure. For example, the user can directly contact the conductive structure or can be capacitively coupled to the conductive structure.
Implementation Method 2
The antenna element can include a plurality of portions, the plurality of portions coupled to define a capacitively loaded dipole antenna.
Data Source
AI summary
An antenna configured for low frequency applications on a mobile device includes an antenna element coupled to a conductive structure which, in turn, is coupled to the user of the mobile device such that the user of the mobile device effectively becomes part of the antenna. The conductive structure can include, for example, the device housing being made from a conductive material, a conductive structure embedded inside the device housing, or conductive pads exposed in the device housing. The antenna element is electrically connected to the conductive structure and the user can be coupled to the conductive structure either through direct contact or through capacitive coupling.