Multi-Band Antenna Impedance Matching via Reactive Load
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Solution Overview
Problem
Designing a compact, multi-band radio frequency antenna element with acceptable efficiency across various frequency bands is challenging due to the relationship between antenna size, electrical length, and resonant modes, as well as the need for separation from conducting components, which limits device miniaturization and efficient operation in multiple communication bands.
Innovation Solution
A multiple-resonance antenna arrangement with a load comprising reactive components that change impedance between inductive and capacitive modes across different frequency bands, using microwave circuit components to provide a broader bandwidth and improved matching with radio frequency circuitry, allowing for efficient operation in both the US-GSM850/EGSM 900 and mobile cellular telecommunication bands.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the antenna element size is reduced to make the device smaller, then the device size is reduced, but the antenna efficiency and performance deteriorate due to the relationship between physical size, electrical length, and resonant modes
Solution Approach 1:
The patent applies parameter changes by introducing reactive components (capacitors and inductors) that modify the electrical characteristics of the antenna system. These components change the impedance parameters to achieve resonance at multiple frequencies, allowing the antenna to maintain efficient operation across different frequency bands despite the reduced physical size of the antenna element.
Solution Approach 2:
The patent uses reactive components as intermediary elements between the antenna element and the ground plane. These intermediary components (capacitors and inductors) mediate the electrical interaction, allowing the antenna to achieve desired resonant modes and impedance matching without requiring a large separation distance from the ground plane, thus enabling device miniaturization while maintaining performance.
2Reliability
If the antenna element is separated from the ground plane by a larger distance to achieve acceptable performance, then the antenna efficiency is improved, but the minimum device size increases
Solution Approach 1:
The patent changes the electrical parameters by introducing reactive components that compensate for the reduced separation distance. The capacitors and inductors are selected with specific values to achieve the desired impedance transformation and resonance, allowing the antenna to operate efficiently even when positioned closer to the ground plane, thus reducing the overall device volume.
Solution Approach 2:
The reactive components serve as intermediary elements that enable the antenna to achieve proper impedance matching and resonance without requiring a large physical separation from the ground plane. These intermediaries effectively extend the electrical length and modify the resonant characteristics, allowing efficient operation in a compact configuration.
3Device complexity
If a single antenna element is designed to operate in multiple frequency bands, then the device complexity is reduced, but achieving acceptable efficiency in all bands becomes difficult
Solution Approach 1:
The patent implements multi-functionality by designing a single antenna element with associated reactive components that can operate across multiple frequency bands. The antenna element combined with the tunable reactive components serves multiple functions: it can be adjusted to resonate at different frequencies (first and second frequency bands) and maintain efficient operation in each band, eliminating the need for separate antenna elements for different bands.
Solution Approach 2:
The patent applies dynamics by making the antenna system adjustable and reconfigurable. The reactive components (capacitors and inductors) can be tuned or switched to different values, allowing the antenna to dynamically adapt its resonant frequency and impedance characteristics to operate efficiently in different frequency bands as required, providing a versatile multi-band solution.
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 enables a wider bandwidth and higher efficiency with a lower profile, allowing for better impedance matching and operational flexibility across multiple frequency bands, thereby addressing the constraints of size and performance in compact devices.
Implementation Method 1
a multiple-resonance antenna element having a feed for connection to radio frequency circuitry; and an antenna load comprising a plurality of reactive components including a first reactive component that controls the impedance of the load for the first radio communication band and a second reactive component, separate from the first reactive component, that controls the impedance of the load for the second radio communication band
Data Source
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Figure 7~8
AI summary
An antenna arrangement (10) for radio communication in a first radio communication band and for communication in a second radio communication band includes a multiple-resonance antenna element (10) having a feed (12) for connection to radio frequency circuitry (4); and a load (21) connected to the feed (12). The antenna arrangement (10) comprises a plurality of reactive components including a first reactive component that controls the impedance of the load (21) for the first radio communication band and a second reactive component, separate from the first reactive component, that controls the impedance of the load for the second radio communication band. The plurality of reactive components of the load (21) are configured to provide an impedance that changes between being inductive at a first frequency in the first radio communication band to being capacitive at a second frequency in the first radio communication band and that changes between being inductive at a third frequency in the second radio communication band to being capacitive at a fourth frequency in the second radio communication band.