Embedded Multiband Antenna Design for Reduced Coupling
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Solution Overview
Problem
Existing multiband antennas suffer from gain loss and poorly shaped radiation patterns due to near-field coupling and inadequate frequency isolation, leading to inefficient operation across multiple frequency bands, particularly in compact designs for vehicles and handheld devices.
Innovation Solution
The integration of a folded dipole element within a monopole antenna structure, where the folded dipole is approximately half-wavelength long at a secondary resonant frequency, allows for independent operation across multiple frequency bands with reduced mutual interference, enhancing radiation patterns and impedance matching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple separate antennas are used for different frequency bands, then frequency coverage is improved, but device size and complexity increase
Solution Approach 1:
The patent combines multiple antenna elements (full-wave monopole and folded dipole) into a single integrated antenna structure that operates across multiple frequency bands. The monopole element handles lower frequencies while the embedded folded dipole handles higher frequencies, eliminating the need for separate antennas and reducing overall system complexity.
Solution Approach 2:
The integrated antenna structure serves multiple functions across different frequency bands. The same physical structure supports both the monopole resonance for lower bands and the folded dipole resonance for higher bands, making the antenna system universal rather than requiring band-specific antennas.
2Volume of moving object
If antenna size is reduced for miniaturization, then device compactness is improved, but radiation efficiency deteriorates
Solution Approach 1:
The folded dipole element is nested within the monopole element structure. The folded dipole is positioned inside the monopole's physical boundaries, allowing both elements to coexist in a compact volume. This nesting enables full-wave resonance at lower frequencies while accommodating the folded dipole's half-wave resonance at higher frequencies without increasing overall antenna size.
Solution Approach 2:
The folded dipole is oriented perpendicular to the monopole element, utilizing a different spatial dimension. This orthogonal arrangement allows both elements to operate independently in different dimensional orientations, maintaining their respective resonance characteristics while fitting within a compact overall structure.
3Volume of moving object
If multiple antenna elements are integrated closely, then device compactness is improved, but near-field coupling and interference increase
Solution Approach 1:
The folded dipole element is positioned asymmetrically within the monopole structure, offset from the centerline. This asymmetric placement creates unequal current distribution and reduces symmetric coupling paths between the elements. The folded dipole's perpendicular orientation further enhances this asymmetry, minimizing near-field interference while maintaining compact integration.
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 configuration results in improved radiation patterns with increased symmetry and reduced interference, achieving efficient operation across multiple frequency bands with enhanced gain and reduced size, suitable for compact applications such as vehicles and handheld devices.
Implementation Method 1
the folded dipole is approximately half-wavelength long at a secondary resonant frequency, allows for independent operation across multiple frequency bands
Implementation Method 2
An antenna can include one or more structural electrical elements each providing a bi-directional transition between a guided electrical wave and a free-space propagating wave
Data Source
AI summary
A multiband antenna includes one or more first antennas embedded within a second antenna. The one or more first antennas can include a folded dipole, and the second antenna can include a monopole. The folded dipole and the monopole may operate at different resonant frequencies. Because the folded dipole is embedded in the monopole, rather than being a separate antenna, near-field coupling between the antennas may be reduced, resulting in enhanced radiation patterns by one or both antennas. More complex antenna structures can also be constructed having multiple antennas embedded within one or more antennas.