MEMS Accelerometer Phase Shifter Angle Sensing for Antenna Downtilt
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Solution Overview
Problem
Existing base station antennas face challenges in accurately and remotely determining the position of phase shifter arms, as traditional sensors like potentiometers degrade and are not directly correlated with the phase shifter arm position, and default tilt angles are not remotely detectable.
Innovation Solution
A rotating wiper-type phase shifter system with a stationary and rotatable circuit board, utilizing a digital accelerometer to provide signals indicative of the physical angle, and a look-up table to correlate angles with desired beam attributes, allowing for precise adjustment of beam downtilt angles through a controller and motor actuator.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If potentiometers are used to determine the position of the phase shifter arm, then the position can be measured, but the performance degrades over time leading to inconsistent measurements
Solution Approach 1:
The patent replaces the mechanical potentiometer-based position sensing system with an accelerometer-based measurement system. The accelerometer directly measures the physical angle of the phase shifter arm relative to vertical, eliminating the mechanical wear and degradation issues inherent in potentiometers. This substitution provides more reliable and consistent position measurements throughout the sensor's operational life.
2Loss of information
If markings on a linkage rod are used to determine phase angle, then the position information is available, but the markings cannot be determined remotely from the site
Solution Approach 1:
The patent implements a feedback system where the accelerometer continuously measures the phase shifter arm's physical angle and provides this information to a controller. The controller can remotely access this position data and compare it with the desired position, enabling remote monitoring and adjustment of the antenna beam attributes without requiring physical inspection of markings on the linkage rod.
3Measurement precision
If the accelerometer is disposed on the rotatable circuit board, then direct measurement of the phase shifter arm position is achieved, but the device complexity increases
Solution Approach 1:
The patent merges the accelerometer with the rotatable circuit board assembly, integrating the sensing function into an existing structural component. This integration approach allows direct measurement of the phase shifter arm position while minimizing additional complexity by utilizing the circuit board's rotational movement as the mounting platform for the accelerometer.
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
Enables robust, accurate, and remote adjustment of beam attributes by directly measuring the physical angle of the phase shifter arm, improving the reliability and precision of antenna beam control without the need for additional sensors on coupled elements.
Implementation Method 1
an accelerometer disposed on the rotatable circuit board and oriented such that it provides a signal indicative of a physical angle of the rotatable circuit board with respect to vertical
Implementation Method 2
The rotatable circuit board includes an input and a coupling section, the coupling section located to capacitively couple an input signal to the at least one transmission line
Data Source
AI summary
A physical angle of a portion of a variable element, such as a phase shifter, is used to determine a desired antenna beam attribute, such as beam downtilt. In one example, a variable element includes a stationary circuit board and a rotatable circuit board. The stationary circuit board has at least one transmission line having a first output and a second output. The rotatable circuit board includes an input and a coupling section, the coupling section located to capacitively couple an input signal to the at least one transmission line between the first output and the second output, and the accelerometer being oriented such that it provides a signal indicative of a physical angle of the rotatable circuit board with respect to vertical.