Antenna Array Sidelobe Suppression via Dynamic Weighting
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Solution Overview
Problem
Active antenna arrays face challenges in efficiently adjusting sidelobes and downtilt angles to minimize interference between cells, especially due to mechanical downtilting and transceiver failures, which result in power loss and distortion of radiation patterns.
Innovation Solution
A digital radio interface connects the antenna array to a signal processor that weights transceiver signals using complex values to automatically compensate for power losses and adjust sidelobes, with a failure detector monitoring transceivers and adjusting downtilt angles to optimize radiation patterns, and a look-up table storing complex values for phase and amplitude adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If fixed amplitude tapering is used to suppress sidelobes for all downtilt values, then sidelobe interference is reduced, but overall antenna gain is lowered
Solution Approach 1:
The patent employs dynamic amplitude weighting that adapts to the current downtilt angle rather than using fixed tapering. The weighting factors are recalculated based on the actual tilt configuration, allowing optimal sidelobe suppression for each specific angle. This dynamic approach maintains higher overall gain compared to fixed tapering while still achieving the required sidelobe suppression performance.
2Adaptability or versatility
If beam forming with digital signal processing is used to achieve flexible downtilting, then downtilt adjustability is improved, but the relationship between main lobe and sidelobes is affected causing unacceptable interference
Solution Approach 1:
The patent applies position-dependent amplitude weighting to antenna elements, where elements at different locations in the array receive different weight factors. This local differentiation suppresses sidelobes that would otherwise be elevated by beam forming operations, resolving the interference issue while preserving the flexibility of digital downtilt adjustment.
3Reliability
If transceiver failure occurs in active antenna arrays, then overall power is degraded, but distortion of radiation patterns increases sidelobe strength causing unwanted interference
Solution Approach 1:
The patent implements a monitoring system that detects transceiver failures and automatically adjusts the weighting factors of remaining functional elements. When a transceiver fails, the system recalculates the amplitude and phase weights to compensate for the missing element, maintaining the desired radiation pattern and sidelobe suppression. This feedback mechanism resolves the contradiction by adapting to failures while preventing sidelobe elevation.
Data Source
AI summary
An antenna array for the transmission of signals is disclosed which comprises a plurality of antenna elements connected to a plurality of transceivers. The plurality of transceivers receive transceiver signals for transmission to the plurality of antenna elements. The antenna comprises a failure detector or monitoring and control system connected to the plurality of transceivers, which autonomously detects malfunction of the individual transceivers and reports this to the signal processor without involvement of the transmitter and receiver. The antenna array also comprises a signal processor connected to the plurality of transceivers and adapted to weight using complex values the transceiver signals for automatically compensating for power losses by tilt adjustments and for interference by suppression of sidelobes of the signals based on the information from the failure detector or monitoring and control system.