Shared-Element Base Station Antennas for Stable Azimuth Beamwidth
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Solution Overview
Problem
Designing base station antennas that can operate across the full 1427-2690 MHz frequency band while maintaining suitable azimuth beamwidths at both lower and upper frequency ends is challenging, as the beamwidth tends to vary significantly with frequency, affecting coverage and interference patterns.
Innovation Solution
The use of two or more arrays of radiating elements that share one or more radiating elements, with frequency-dependent circuit elements like diplexers and power dividers to adjust the azimuth beamwidth, allowing the antenna to maintain consistent beam shapes across the frequency band by reducing beamwidth in lower frequency ranges and minimizing changes in higher frequency ranges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a linear array of radiating elements is used to provide coverage in the 1427-2690 MHz frequency band, then the antenna can support multiple cellular services, but the azimuth beamwidth varies significantly with frequency, affecting coverage consistency
Solution Approach 1:
The frequency band is segmented into lower (1427-1710 MHz) and upper (1710-2690 MHz) portions, with different radiating element configurations activated for each segment. This allows the antenna to optimize beamwidth characteristics for each frequency range independently, resolving the contradiction between broad frequency coverage and beamwidth consistency.
Solution Approach 2:
The antenna system dynamically switches between different radiating element configurations based on the operating frequency. Circuit elements such as switches or diplexers enable the system to adapt the active radiating elements according to the frequency band in use, maintaining stable beamwidth characteristics across the full frequency range.
2Stability of the object's composition
If additional radiating elements are added to reduce azimuth beamwidth at lower frequencies, then coverage consistency improves, but device complexity and cost increase
Solution Approach 1:
Each radiating element is designed to serve multiple frequency ranges, with circuit elements enabling each element to be activated or deactivated based on the operating frequency. This multi-functional approach allows the same physical structure to optimize performance across different bands without requiring separate dedicated elements for each frequency range.
Solution Approach 2:
The electrical characteristics of the radiating elements are modified through circuit elements (such as impedance matching networks or switching configurations) to optimize performance for different frequency ranges. This allows the same physical elements to present different electrical parameters appropriate for each frequency band, reducing the need for additional hardware.
3Reliability
If separate base station antennas are deployed for different frequency bands, then optimal performance for each band is achieved, but the number of antennas exceeds zoning and structural limits
Solution Approach 1:
Multiple frequency band capabilities are merged into a single base station antenna structure. The antenna integrates radiating elements and circuitry that can operate across lower and upper frequency bands, eliminating the need for separate antennas for each band while maintaining optimal performance characteristics.
Solution Approach 2:
The base station antenna is designed as a universal structure capable of supporting multiple cellular services across different frequency bands. Through intelligent switching and circuit element configuration, a single antenna performs the function of what would traditionally require multiple specialized antennas.
Data Source
Figure 1~2A
Figure 2B~2C
Figure 3A
AI summary
Base station antennas include a first array of radiating elements that is coupled to a first RF port through a first feed network, a second array of radiating elements that is coupled to a second RF port through a second feed network, and first and second circuit elements. The first circuit element has a first port coupled to the first feed network, a second port coupled to a first port of the second circuit element and a third port coupled to a first radiating element of the first array of radiating elements. The second circuit element has a second port coupled to a first radiating element of the second array of radiating elements and a third port coupled to the second feed network.