Phase Controller for Antenna Array Using PLL Synthesizers
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Solution Overview
Problem
Conventional phase controllers for antenna arrays suffer from phase imbalance and gain mismatch, leading to phase errors and amplitude errors in the radiation field pattern, and lack high precision and low phase noise in frequency control.
Innovation Solution
A phase controller using phase-coherent PLL frequency synthesizers based on a congruence modulo equation to select and generate frequency signals with precise phases, ensuring accurate radiation field patterns by determining a direction index and calculating a phase index to control the antenna array's main radiating direction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional phase shifters are used to control antenna array phases, then the radiation field pattern can be controlled, but phase imbalance and gain mismatch cause phase errors and amplitude errors
Solution Approach 1:
The patent replaces conventional phase shifters with a PLL-based frequency synthesizer system. The PLL generates multiple frequency signals with precise phase relationships through electronic feedback control, eliminating the need for physical phase shifters and their associated phase imbalance and gain mismatch problems.
Solution Approach 2:
The patent introduces a PLL frequency synthesizer as an intermediary device between the control signal and the antenna array. This intermediary generates intermediate frequency signals with accurate phase relationships, which are then converted to the final output signals for the antenna elements, ensuring precise phase control.
2Ease of operation
If coupled VCOs are used in PLLs for injection and locking, then phase control is achieved, but high phase noise exists in the output signals and output frequency is not accurate
Solution Approach 1:
The patent extracts the VCO coupling mechanism from the system and replaces it with independent PLL frequency synthesizers. Each synthesizer operates independently with its own feedback loop, eliminating the phase noise propagation that occurs when VCOs are coupled together for injection and locking.
Solution Approach 2:
The patent uses multiple independent PLL frequency synthesizers that are configured to generate signals with identical frequency and precise phase relationships. Instead of coupling VCOs to copy signals, each synthesizer independently generates its signal based on the same reference frequency and control logic, producing accurate outputs without phase noise contamination.
3Ease of operation
If multiple PLLs are used to control antenna array phases, then frequency control is achieved, but lack of high precision reference signal source results in phase noise and frequency inaccuracy
Solution Approach 1:
The patent merges multiple PLL frequency synthesizers into a unified system that shares a common high-precision reference signal source. This consolidation ensures that all synthesizers are locked to the same reference frequency, eliminating frequency drift and phase noise while maintaining the ability to control multiple antenna elements independently.
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
The solution achieves low phase and amplitude errors, high frequency precision, and correct desired radiation field patterns for antenna arrays, improving the overall performance of communication apparatuses.
Implementation Method 1
L phase-coherent PLL frequency synthesizers respectively receive the L first frequency signals with the L different first phases to generate L second frequency signals with L different second phases
Data Source
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Figure 1B
Figure 2
AI summary
A phase controller for an antenna array includes a determination circuit, determining a direction index of the antenna array, and calculating a phase index according to the direction index according to a congruence modulo equation; a switching box, selecting L first frequency signals with L different first phases among K first frequency signals with K different first phases according to the phase index, wherein L and K are integer larger than 1, and L is not larger than K; and a frequency synthesizing module, comprising L phase-coherent PLL frequency synthesizers for receiving the L first frequency signals with the L different first phases to generate L second frequency signals with L different second phases to L antennae of the antenna array, wherein a second frequency of the second frequency signals is larger than a first frequency of the first frequency signals.