Multi-band Antenna Feeder with Sub-wavelength Elements
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Solution Overview
Problem
Conventional multi-band antennas for terrestrial wireless networks face challenges in achieving high performance and flexibility while maintaining a compact design at low cost, particularly in urban environments where tower resources are scarce, and they struggle with maintaining a stable phase center across different frequency bands, leading to inefficiencies in antenna efficiency, peak gain, and sidelobe patterns.
Innovation Solution
A multi-band antenna design featuring a single parabolic dish reflector with a feeder assembly that includes sub-wavelength elements with different dielectric constants, arranged along the longitudinal direction of the feeder, which minimizes phase center displacement and maintains a stable phase center, enabling wide-band operation with constant performance in terms of efficiency, peak gain, and sidelobe patterns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a single parabolic dish reflector is used for multi-band operation, then tower resources are optimized and deployment complexity is reduced, but the phase center becomes unstable across different frequency bands
Solution Approach 1:
The patent introduces a dielectric member with specifically engineered local properties (dielectric constant, length, and position) within the feeder assembly. This dielectric member creates localized electromagnetic field modifications that counteract the natural phase center drift toward the open end, thereby stabilizing the overall phase center position across multiple frequency bands while maintaining the single-dish multi-band capability
2Reliability
If traditional antenna designs are optimized for specific frequency bands, then performance within those bands is maximized, but performance deteriorates in higher frequency bands due to phase center displacement
Solution Approach 1:
The patent employs a dielectric member with specific electromagnetic parameters (dielectric constant, length, and radial position) that are optimized to maintain stable phase center characteristics across a broad frequency range. By carefully selecting and positioning this dielectric element, the antenna achieves consistent performance reliability from several GHz up to hundreds of GHz, enabling true multi-band operation with a single dish reflector
3Reliability
If multiple dish antennas are used for separate microwave and millimeter-wave transmission, then band-specific performance is optimized, but tower construction complexity and cost increase
Solution Approach 1:
The patent designs a universal feeder assembly that can handle multiple frequency bands (microwave and millimeter-wave) through a single integrated structure. The dielectric member enables this feeder to maintain stable electromagnetic characteristics across wide frequency ranges, allowing one parabolic dish to replace multiple specialized antennas, thereby simplifying tower construction and reducing installation complexity while maintaining reliable band-specific 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 proposed solution allows for a stable phase center across various frequency bands, resulting in consistent antenna performance, including efficient operation, peak gain, and sidelobe patterns, while reducing manufacturing complexity and cost, thus meeting stringent ETSI EN 302 standards.
Implementation Method 1
The sub-wavelength element has a dielectric constant different than the dielectric constant of the dielectric emitting section
Data Source
Figure 1(a)~1(c)
Figure 2
Figure 3
AI summary
The present invention provides an antenna feeder assembly of a multi-band antenna, comprising a first feeder supporting propagation of waves in a first frequency band and a second feeder supporting propagation of waves in a second frequency band lower than the first frequency band, wherein: the second feeder coaxially surrounds the first feeder, and the first feeder comprises a dielectric emitting section and a dielectric radiating section; wherein each of the dielectric emitting section and the radiating section includes an inner cavity, a wall, and sub-wavelength elements on an external surface of the wall. The present invention also provides a multi-band microwave antenna, comprising a dish reflector, a subreflector, and an antenna feeder assembly according to the aforementioned first aspect of the present invention.