Log-Periodic Antenna Compact Design for Wide Band
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Solution Overview
Problem
Existing wide frequency band antennas are bulky, making them unsuitable for compact applications such as on-board systems, as their dimensions in the direction of wave propagation are of the order of the wavelength corresponding to the lowest frequency.
Innovation Solution
A log-periodic antenna design featuring three radiating elements with a log-periodic pattern positioned above a substrate, where the radiating elements have increasing dimensions from one end to the other, and are arranged symmetrically with inclined conductive lines to reduce overall size while maintaining constant illumination over a wide frequency band.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If traditional wide frequency band antenna configurations are used, then constant illumination over a wide frequency band is achieved, but the antenna dimensions become bulky (of the order of the wavelength corresponding to the lowest frequency)
Solution Approach 1:
The patent transitions from traditional planar antenna configurations to a three-dimensional folded structure. The conductive elements are arranged in multiple planes and folded back on themselves, utilizing vertical and lateral spatial dimensions to achieve compactness while preserving the electrical length required for wide frequency band operation
Solution Approach 2:
The antenna employs a nested configuration where conductive elements are folded and layered within a compact volume. The first and second conductive elements are positioned in different planes and folded arrangements, effectively nesting the antenna structure within itself to reduce overall dimensions while maintaining functional performance
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 design achieves a compact structure with consistent radiation patterns across a wide frequency band, specifically optimized for the 2 GHz - 4 GHz range, with an angular aperture of 25° - 28° over the entire band, ensuring efficient operation without the bulkiness of traditional antennas.
Implementation Method 1
each radiating element with a log-periodic pattern comprising a succession of radiating dipoles distributed on either side of a rectilinear electrically conductive line
Implementation Method 2
a substrate which defines an electrical ground of the antenna
Data Source
Figure 1~2A
Figure 2B~3B
Figure 4~5A
AI summary
The invention relates to a log-periodic antenna which comprises at least one set of three radiating elements with log-periodic patterns (E1, E2, E3) positioned above a first face of a flat substrate (3), each radiating element comprising a succession of radiating dipoles distributed on either side of a rectilinear electrically conducting line (R1, R2, R3), perpendicular to said line, the radiating dipoles having a dimension which increases between a first end of said line and a second end of said line situated nearer to the first face than the first end, a first radiating element (E2) having a rectilinear electrically conducting line substantially perpendicular to the first face of the substrate (3), the first ends of the electrically conducting lines of the various radiating elements being substantially aligned along a direction parallel to the first face, the rectilinear electrically conducting lines of the second and third radiating elements being situated in one and the same plane as the rectilinear electrically conducting line of the first radiating element and being inclined with respect to the electrically conducing line of the first radiating element, the radiating dipoles of the three radiating elements being substantially perpendicular to the plane which contains the rectilinear electrically conducting lines of the three radiating elements.