Loop Antenna with Opposing Conductor for Wide Bandwidth
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Solution Overview
Problem
Existing antenna apparatus for portable devices face challenges in widening the frequency band due to their compact size, which limits the impedance adjustment and results in narrow frequency bandwidth performance.
Innovation Solution
The antenna apparatus is configured with a ground conductor on one face of a dielectric substrate and a loop antenna with matching circuits on both ends, along with a conductor on the opposing face, electromagnetically coupled to achieve dual or triple resonance characteristics, allowing for impedance adjustment and widening the frequency band with minimal increase in antenna size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the antenna length is increased to widen the frequency band, then the frequency band width is improved, but the device size increases which compromises portability
Solution Approach 1:
The patent utilizes the third dimension by forming the loop antenna and conductor on opposite faces of a dielectric substrate, creating a three-dimensional electromagnetic coupling structure. This vertical arrangement allows the antenna to achieve wider frequency band characteristics without increasing the planar footprint, effectively resolving the contradiction between frequency band width and device size for portable applications
Solution Approach 2:
The patent changes the electromagnetic parameters by introducing a conductor with different dimensions and impedance characteristics than the loop antenna. By adjusting the conductor's length, width, and position relative to the loop antenna, the system achieves impedance matching and widens the frequency band (VSWR≤2) without requiring proportional increases in antenna size
2Volume of moving object
If the antenna is made compact for portability, then the device size is reduced, but the frequency band width becomes narrow due to limited antenna length
Solution Approach 1:
The patent exploits the vertical dimension by placing the loop antenna on one face of the dielectric substrate and the conductor on the opposite face. This three-dimensional configuration enables compact planar dimensions while achieving wide frequency band characteristics through electromagnetic coupling across the substrate thickness, effectively decoupling size from frequency band performance
Solution Approach 2:
The patent introduces adjustable matching circuits that dynamically optimize the impedance matching between the loop antenna and conductor. By making the impedance characteristics adjustable rather than fixed, the system can adapt to different frequency conditions within the compact structure, maintaining wide bandwidth performance without increasing size
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 enables a wider frequency band operation with improved impedance matching, achieving a wide-band characteristic while maintaining a compact antenna size, enhancing the antenna's performance and flexibility.
Implementation Method 1
a conductor 2 having matching circuits 8, 9 connected respectively to both ends thereof and having a wavelength shorter than that of a frequency band to be used is provided on a second face, which is the other face of the dielectric substrate with the intermediary of the dielectric substrate 4 so as to be electromagnetically coupled and resonant with the loop antenna 1
Implementation Method 2
a conductor 2 having matching circuits 8, 9 connected respectively to both ends thereof and having a wavelength shorter than that of a frequency band to be used is provided on a second face, which is the other face of the dielectric substrate with the intermediary of the dielectric substrate 4 so as to be electromagnetically coupled and resonant with the loop antenna 1
Data Source
AI summary
A ground conductor constituting a bottom board and a loop antenna formed of a strip conductor formed separately from and around the ground conductor are provided on one face of a dielectric substrate, and a transmitter-receiver is connected to one end of the loop antenna serving as the power dispatching unit via a first matching circuit, and a second matching circuit is connected to the other end. A conductor formed of the strip conductor is provided on the dielectric substrate on the other face of the dielectric substrate so as to oppose the loop antenna with the intermediary of the dielectric substrate. A third matching circuit is connected to one end of the conductor and a fourth matching circuit is connected to the other end of the conductor. The loop antenna and the conductor are set to have a wavelength shorter than that of the frequency band to be used.