Dielectrically-Loaded Helical Antenna Dual-Band Operation
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Solution Overview
Problem
Existing dielectrically-loaded antennas lack sufficient frequency coverage and bandwidth to effectively operate with circularly polarized electromagnetic radiation at frequencies above 200 MHz, particularly for satellite communication and navigation systems.
Innovation Solution
A dielectrically-loaded helical antenna design featuring a solid dielectric core with a high dielectric constant, paired feed coupling nodes, and a unique arrangement of elongate conductive antenna elements of different electrical lengths, allowing for dual-band operation with circularly polarized radiation, enabling operation across multiple frequency bands including satellite communication and navigation services.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a conventional dielectrically-loaded antenna is used, then the antenna structure is simple, but the frequency coverage and bandwidth are insufficient for operations above 200 MHz
Solution Approach 1:
The antenna elements are divided into multiple groups (first group and second group) with different electrical lengths, where each group is associated with different operating frequencies. This segmentation allows the antenna to operate at multiple frequency bands while maintaining a structured and manageable configuration.
Solution Approach 2:
Different portions of the antenna elements have different electrical lengths, creating local variations in electrical characteristics. The first group of antenna elements has different electrical lengths than the second group, allowing each local region to be optimized for specific frequency operations, thereby achieving broader frequency coverage.
2Adaptability or versatility
If antenna elements of different electrical lengths are used to achieve dual-band operation, then frequency coverage is improved, but the antenna element arrangement complexity increases
Solution Approach 1:
The antenna elements are designed with asymmetric electrical lengths within and between groups. The first group of antenna elements has different electrical lengths than the second group, creating an asymmetric structure that enables dual-band operation by resonating at different frequencies while maintaining circular polarization characteristics.
Solution Approach 2:
The antenna structure is designed to perform multiple functions simultaneously: it supports dual-band operation, maintains circular polarization, and provides impedance matching. The common interconnecting conductor and feed coupling nodes serve universal functions for both frequency bands, reducing overall system complexity despite the multi-band capability.
3Volume of moving object
If a high dielectric constant material is used to reduce antenna size, then the physical dimensions are reduced, but the manufacturing precision requirements increase
Solution Approach 1:
The invention utilizes a dielectric material with a high dielectric constant (greater than 5) to reduce the physical size of the antenna. By changing the dielectric parameter of the core material, the electrical length of the antenna elements is increased for a given physical length, allowing the antenna to achieve resonant frequencies at smaller dimensions while maintaining the required electrical characteristics.
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 achieves dual-band operation with circularly polarized radiation, providing enhanced frequency coverage and bandwidth, suitable for satellite telephone services and dual-service systems like GPS and Galileo, with improved efficiency and reduced size.
Implementation Method 1
an electrically insulative dielectric core of a solid material that has a dielectric constant greater than 5 and occupies the major part of the interior volume defined by the core outer surface
Implementation Method 2
an antenna element structure that includes a plurality of elongate conductive antenna elements and a common interconnecting conductor... with circularly polarised radiation
Implementation Method 3
the said groups containing electrically short antenna elements associated with a circular polarisation resonance at the first frequency and electrically long antenna elements associated with a circular polarisation resonance at the second frequency
Data Source
AI summary
A dual-band dielectrically loaded helical antenna for circularly polarised signals has two groups of helical antenna elements. In each group there are at least four such elements and they are connected at their distal ends to a respective feed coupling node and at their proximal ends to a common linking conductor. Each group includes pairs of neighbouring such antenna elements, each pair having one electrically short element and one electrically long element, and the arrangement of the elements is such that in each group the number of pairs in which, in a given direction around the core, the short element precedes the long element is equal to the number of pairs in which, in the same direction, the long element precedes the short element.