Multiband Dismount Antenna Current Distribution Control
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Solution Overview
Problem
Conventional antennas face limitations in bandwidth due to input impedance, gain, and radiation pattern issues, particularly as frequency increases, leading to undesirable radiation pattern distortions and nulls in the direction orthogonal to the antenna length, which restrict the useful operating frequency range.
Innovation Solution
The use of inductors to modify the current distribution in dipole and monopole antennas, with numerical modeling for optimizing inductor values and sub-element lengths, ensures a radiation pattern peak remains orthogonal to the antenna length across a wide range of wavelengths, thereby extending the pattern wavelength range and maintaining gain consistency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional antenna designs are used, then the antenna operates at specific frequencies, but the radiation pattern develops deep nulls and distortions as frequency increases, limiting the useful bandwidth
Solution Approach 1:
The antenna element is divided into multiple sub-elements with different lengths, where each sub-element contributes to the overall radiation pattern in a specific frequency range. This segmentation allows the antenna to maintain consistent radiation patterns across a broader frequency spectrum by preventing the formation of deep nulls that occur in conventional single-length designs.
Solution Approach 2:
Different sub-elements are assigned different lengths to optimize performance at different frequencies. The longer sub-elements contribute more at lower frequencies while shorter sub-elements maintain performance at higher frequencies, creating a non-uniform local quality distribution that collectively solves the bandwidth limitation problem.
2Adaptability or versatility
If inductors are added to modify current distribution, then the radiation pattern is improved and bandwidth is extended, but the device complexity increases
Solution Approach 1:
The inductor is integrated directly into the antenna structure by forming it as part of the radiating element itself, rather than adding it as a separate discrete component. This merging approach extends the pattern wavelength range while minimizing additional complexity, as the inductor becomes an inherent part of the segmented antenna structure.
3Adaptability or versatility
If the antenna length is increased to extend bandwidth, then the low-frequency performance improves, but the high-frequency radiation pattern becomes distorted with nulls in the desired direction
Solution Approach 1:
Instead of using a single long antenna element that causes high-frequency nulls, the structure is segmented into multiple sub-elements of different lengths. The longer sub-elements provide good low-frequency performance while the shorter sub-elements prevent the formation of nulls at high frequencies, allowing the antenna to achieve both low-frequency extension and high-frequency stability simultaneously.
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 approach significantly enhances the antenna's radiation pattern by eliminating deep nulls and maintaining peak gain in the desired direction over a broader frequency range, extending the useful bandwidth and ensuring consistent performance across the pattern wavelength range.
Implementation Method 1
exciting a monopole antenna including an elongated conductive radiating element having an overall length l with a radio frequency signal to produce an oscillating time varying electric current within the elongated conductive radiating element
Data Source
AI summary
Antennas and methods for controlling antennas for producing electromagnetic radiation in a desired direction over a wide range of wavelengths. A current distribution is controlled (e.g. by one or more inductors 102,108) in one or more conductive radiating elements (101a,101b,107) of an antenna (100,106) to form, at every wavelength within a pattern wavelength range, an antenna radiation pattern having a peak in a direction substantially orthogonal to a length of an elongated conductive radiating element or elements (101a,101b,107). By careful control of the current distribution, the pattern wavelength range is made exceptionally broad. In the case of a dipole antenna (100), the pattern wavelength can range from about 1/3l to at least about 8l, where l is an approximate combined length of a pair of elongated elements (101a,101b) forming a dipole antenna (100). Alternatively, in the case of a monopole antenna (106), the pattern wavelength range can extend from about 1/6l to at least about 4l, where l is an approximate overall length of the monopole antenna (106).