Low-Profile Broadband Antenna Using Multiaxial Cable Impedance Matching
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Solution Overview
Problem
Existing antenna systems face challenges in achieving a wide frequency band coverage with thin radiating elements while maintaining a low profile, as they often require the use of 'stubs' that increase size or thick radiating elements that contradict the goal of minimizing antenna size.
Innovation Solution
A low-profile broadband multiple antenna system is designed with dipoles arranged in a collinear configuration, using a multiaxial cable with concentric sheaths and a magnetic core for impedance matching, eliminating the need for 'stubs' and allowing for thin radiating elements to cover a wide frequency band without increasing the antenna's size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If stubs are used to achieve wide frequency band coverage, then bandwidth is improved, but antenna size and profile increase
Solution Approach 1:
The invention extracts and eliminates the stub component from the antenna system. By removing the stub that caused size increase, the patent achieves wide frequency band coverage through alternative means (multiaxial cable with concentric sheaths and magnetic core) without the volume penalty of traditional stub structures
Solution Approach 2:
The invention introduces a multiaxial cable with concentric sheaths and a magnetic core as an intermediary component to achieve impedance matching and wide frequency coverage. This intermediary structure replaces the traditional stub and enables broadband operation with a compact, low-profile design
2Adaptability or versatility
If thick radiating elements are used to cover wide frequency bands, then bandwidth is improved, but antenna profile increases
Solution Approach 1:
The invention changes the structural parameters of the radiating elements from thick to thin by using a multiaxial cable configuration with concentric sheaths. This parameter change maintains broadband capability through the magnetic core coupling mechanism while achieving a low-profile appearance with reduced transverse dimensions
3Volume of moving object
If multiple dipoles are arranged collinearly to maintain low profile, then antenna size is reduced, but impedance matching becomes difficult
Solution Approach 1:
The multiaxial cable with concentric sheaths serves multiple functions simultaneously: it provides mechanical support for the collinear dipole arrangement, enables impedance matching through the magnetic core, and maintains low-profile geometry. This multi-functional component simplifies the overall design while achieving both compact size and proper impedance matching
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 antenna system effectively covers the UHF band from 225 to 400 MHz with a diameter of 25 mm, offering omnidirectional coverage and spatial diversity, while maintaining a low profile and minimizing size, thus achieving broadband impedance matching and efficient power supply without the use of thick elements.
Implementation Method 1
the high antenna element Dks is connected at one point to the sheath of index (k-1) of the multiaxial cable after the assembly of the core and the sheaths of index (1 to k-1) wind up in Q turns around a magnetic core
Data Source
Figure 1A~2
Figure 3A~4
Figure 5A~5B
AI summary
The invention relates to a low-profile broadband multiple antenna characterised in that said antenna comprises at least the following components arranged as specified below: a dipole D1 arranged in the upper portion of said antenna, said dipole comprising at least one upper antenna component (D1s) connected to the core (140) of a multiaxial cable including a core and n sheaths and in which the bottom basic component (D1b) is connected to the first sheath (141) adjacent to the core (140); a connection device (20, 40) positioned between a top component Dks of a dipole Dk and the bottom component Dkb of said dipole Dk, the top component Dks being connected to the sheath with an index of (k-1) of the multiaxial cable after the assembly of the core (140) and the sheaths with indexes of (1 to k-1) are wound into Q turns (41) around a magnetic core (42) and the bottom component Dkb of the dipole Dk is connected to the sheath with an index of k, and in that said connection device (20, 40) includes at least one single-wire winding with P turns (43) on the same magnetic core (42) connecting said bottom component Dkb of said dipole Dk to the sheath with an index of (k-1), at the point (45) corresponding to the start of the winding (41) in order to perform broadband impedance adaptation and to supply power to the dipole Dk.