Dual-Polarized Array Antenna Beamwidth Control
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Solution Overview
Problem
Existing LTE FDD array antennas face challenges in achieving a 65-degree beamwidth on downlinks due to severe cross-coupling between closely spaced linear arrays, leading to over-wide beamwidths exceeding 65 degrees, which affects network performance.
Innovation Solution
The implementation of a dual-polarized array antenna with uplink-downlink duplexers and beam-forming networks, where two adjacent linear arrays with the same polarization direction form beams with a 65-degree beamwidth using beam-forming networks, while allowing for 8-antenna reception on uplinks through shared duplexers, effectively controlling beamwidth and preventing over-wide radiation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If linear arrays are arranged side by side with narrow space, then the antenna structure is compact, but severe cross-couplings occur and beamwidth exceeds 65 degrees
Solution Approach 1:
The antenna system segments the 8 linear arrays into multiple groups, with each group containing arrays of the same polarization direction. Beam-forming networks are independently configured for each group, allowing precise control of beamwidth for each segment while maintaining overall compact structure. This segmentation enables the system to achieve 65-degree beamwidth requirement without excessive cross-coupling effects.
Solution Approach 2:
Beam-forming networks serve as intermediary components between the linear arrays and the radiation space. These networks process and shape the signals from multiple linear arrays, controlling the beamwidth to exactly 65 degrees. The beam-forming networks act as mediators that transform the narrow-space array configuration into controlled beam patterns, eliminating the direct harmful effect of cross-coupling on beamwidth.
2Reliability
If 8 antennas are used for downlink transmission, then MIMO performance is improved, but beamwidth control becomes difficult and exceeds 65 degrees
Solution Approach 1:
The 8 linear arrays are segmented into multiple groups based on polarization direction, with each group processed by dedicated beam-forming networks. This segmentation allows the system to maintain 8-antenna MIMO capability while achieving precise 65-degree beamwidth control within each group, resolving the conflict between MIMO performance and beamwidth precision.
Solution Approach 2:
The system changes the operational parameters of the antenna arrays by configuring beam-forming networks that adjust signal phases and amplitudes. This parameter control enables the same 8-antenna structure to achieve both MIMO performance and precise 65-degree beamwidth, transforming the system's radiation characteristics without changing the physical array configuration.
3Area of stationary object
If closely spaced linear arrays are used, then space utilization is improved, but cross-coupling causes beamwidth to exceed 65 degrees
Solution Approach 1:
Beam-forming networks are introduced as intermediary devices between the closely spaced linear arrays and the radiation environment. These networks process the signals to achieve precise 65-degree beamwidth control, effectively neutralizing the harmful cross-coupling effects that would otherwise cause beamwidth expansion. The beam-forming networks transform the harmful close-spaced configuration into a controlled radiation pattern.
Solution Approach 2:
The system converts the harmful cross-coupling effects into beneficial beam-shaping capabilities. By using beam-forming networks to process the signals from closely spaced arrays, the cross-coupling interactions are harnessed to achieve precise 65-degree beamwidth control. What would normally be a harmful effect becomes the mechanism for achieving the desired beam pattern.
Data Source
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AI summary
An array antenna and a base station are provided. The array antenna comprises a plurality of linear arrays, uplink-downlink duplexers, and beam-forming networks. Each linear array is a dual-polarized linear array. An input end of the beam-forming network is coupled with a downlink signal output end of a RF(Radio Frequency) unit, and two output ends of the beam-forming network are respectively coupled with downlink signal transmitting ends of two uplink-downlink duplexers; transceiving ends shared by two uplink-downlink duplexers are respectively coupled with arrays having the same polarization direction of two adjacent linear arrays, and the two arrays having the same polarization direction form a beam with 65-degree beamwidth on the downlink through the beam-forming network; uplink signal output ends of the two uplink-downlink duplexers are coupled with uplink signal input ends of the RF unit; linear arrays uncoupled with uplink-downlink duplexers in the plurality of linear arrays are all coupled with the uplink signal input ends of the RF unit respectively. Thereby, a beam with 65-degree beamwidth may be formed by a transmitting antenna on a downlink.