Beam Steering Radar Antenna Calibration Across Angle Variations
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Solution Overview
Problem
Current antenna calibration methods are uncertain and lengthy, especially for larger antenna arrays, and fail to efficiently account for variations in voltage and phase across different transmit/receive angles, leading to performance issues such as gain variance and side lobe discrepancies.
Innovation Solution
A calibration method and apparatus that employs an optimization algorithm, such as gradient descent, to determine sets of input voltages and phase shifts for antenna elements, ensuring accurate radiation patterns across a range of angles by iteratively adjusting voltage and phase settings to converge on optimal values, which are stored in a Look-Up Table for future use.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional antenna calibration methods are used, then calibration can be performed, but the calibration time increases significantly with antenna array size and measurement uncertainty remains high
Solution Approach 1:
The calibration process is segmented into two distinct phases: a fast coarse calibration phase that provides initial estimates, and a refined calibration phase that achieves high precision. This segmentation allows the system to quickly converge to acceptable calibration values without requiring exhaustive measurements, thereby reducing total calibration time while maintaining accuracy.
Solution Approach 2:
The coarse calibration phase performs preliminary adjustments to voltage and phase values before the refined calibration phase. By pre-establishing approximate calibration parameters through the coarse phase, the system reduces the search space and measurement requirements for the subsequent refined phase, eliminating the need for exhaustive calibration measurements.
2Manufacturing precision
If traditional calibration methods are used, then all angles can be measured, but the procedure becomes excessively lengthy for large antenna arrays
Solution Approach 1:
The system performs calibration measurements at a limited set of discrete angles during the coarse calibration phase, which is sufficient to establish initial voltage and phase values. This partial measurement approach provides adequate calibration for practical purposes without requiring exhaustive measurements at all possible angles, thereby significantly improving calibration throughput.
Solution Approach 2:
By performing preliminary coarse calibration at selected angles before refined calibration, the system establishes initial parameters that guide subsequent measurements. This preliminary action reduces the total number of measurements required across all angles, improving productivity while maintaining radiation pattern accuracy.
3Ease of operation
If voltage and phase values are not optimized, then calibration is simpler, but gain variance and side lobe discrepancies occur across different transmit/receive angles
Solution Approach 1:
The calibration system dynamically adjusts voltage and phase values based on measured performance across different angles. Rather than using fixed, simplified calibration values, the system adapts parameters to compensate for variations in the antenna array response, ensuring consistent gain and side lobe levels across all transmit and receive angles while maintaining operational simplicity through automated adjustment.
Solution Approach 2:
The system measures actual radiation patterns at multiple angles and uses this feedback to iteratively refine voltage and phase values. This feedback loop ensures that gain variance and side lobe discrepancies are corrected across different transmit/receive angles, improving performance consistency while keeping the calibration process manageable through systematic adjustment.
Data Source
AI summary
Examples disclosed herein relate to an antenna calibration method for a beam steering radar. A first set of input voltages is determined for a plurality of phase shifters coupled to a plurality of antenna elements in an antenna array in the beam steering radar, the voltages to control phases of signals for transmission by the antenna array. A first set of input voltages is applied to the antenna array. Radiating signals resulting from the first set of input voltages are measured. Voltage and phase values for the plurality of phase shifters are iteratively optimized to determine voltage and phase value pairs that result in a desired gain for the antenna array. The voltage and phase value pairs are stored in a look-up-table in the beam steering radar.