Multi-Band Antenna Stub Layout for High-Band Scattering Control
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Solution Overview
Problem
The challenge in multi-band antenna design is the resonance of low-band radiators in higher-band operating frequencies, which deteriorates the radiation patterns of higher-band radiators due to their large size, leading to scattering issues affecting beam width, beam shape, and cross-polarization levels.
Innovation Solution
The introduction of stubs across the separating point of the dipole ring alters the current path and resonance mode of the induced current on low-band radiators, reducing scattering by re-directing current over high-band radiators, with the length and number of stubs determined by the predefined high frequency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If low-band radiators are made large to radiate low-frequency signals effectively, then low-frequency radiation performance is improved, but the radiators resonate in higher-band operating frequencies and deteriorate the radiation patterns of higher-band radiators
Solution Approach 1:
Stub elements are introduced as intermediary components connected to the low-band radiator at specific points. These stubs act as mediators that redirect induced high-band currents away from the main radiator body, preventing resonance and scattering while allowing the low-band radiator to maintain its large size for effective low-frequency radiation
Solution Approach 2:
The electrical characteristics of the low-band radiator are modified by changing its current distribution parameters through the addition of stubs. By carefully designing the stub lengths and connection points, the resonant frequencies of the low-band radiator are shifted away from the high-band operating frequencies, eliminating the harmful resonance effect
2Adaptability or versatility
If multiple radiators for various bands are densely allocated on the reflector to achieve multi-band functionality, then adaptability across bands is improved, but the low-band radiators shadow the higher-band radiators and cause performance deterioration
Solution Approach 1:
Stub elements serve as intermediary structures that decouple the electromagnetic interaction between low-band and high-band radiators. By redirecting currents through the stubs, the harmful shadowing and scattering effects are eliminated while maintaining the dense allocation of multiple radiators for multi-band adaptability
3Object-generated harmful factors
If stubs are introduced to redirect current and reduce scattering, then high-band radiation performance is improved, but the device complexity increases
Solution Approach 1:
The low-band radiator structure is segmented by introducing discrete stub elements at specific locations. This segmentation allows the radiator to be designed as a modular structure where stubs can be added or removed based on specific band requirements, managing complexity through systematic decomposition
Solution Approach 2:
The stub elements serve multiple functions simultaneously: they redirect high-band currents to prevent scattering, maintain the low-band radiation pattern, and can be configured in various patterns (single stub, multiple stubs, different lengths) to accommodate different multi-band requirements, reducing overall system complexity through multi-functionality
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 reduces radiated power and improves radiation performance, widening the scattering-free bandwidth and enhancing beam shape and cross-polarization characteristics in both azimuth and elevation planes.
Implementation Method 1
the resonance mode of the induced current over the low-band radiator in the high-band
Implementation Method 2
the induced current is re-directed over the high-band on the low-band radiator by introducing the stubs
Data Source
AI summary
Provided are antenna apparatus and a base station, where the antenna apparatus includes a first radiator configured to radiate a low-frequency signal and a second radiator configured to radiate a high-frequency signal, the first radiator comprising at least one first stub and at least one second stub; one end of the first stub is connected to a first connecting point on the first radiator, the other end of the first stub is a free end; one end of the second stub is connected to a second connecting point on the first radiator, the other end of the second stub is a free end; and a sum of a length of the first stub, a length of the second stub, and a length of the first radiator between the first connecting point and the second connecting point is determined according to a wavelength corresponding to a predefined high frequency.