Hybrid Phase Shifter with Digital Control and Temperature Compensation
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Solution Overview
Problem
Existing phase shifters, both analog and digital, face challenges such as high insertion loss, limited bandwidth, and temperature variability, with digital phase shifters requiring negative voltage and analog shifters experiencing phase variation over temperature.
Innovation Solution
A high accuracy phase shift apparatus combining a voltage-controlled analog phase shifter, microcontroller unit, and digital-to-analog converter, which uses a lookup table for precise control and incorporates temperature compensation to achieve stable phase shifts over a wide bandwidth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional digital phase shifters are used to achieve high resolution phase control, then phase resolution is improved, but insertion loss increases and bandwidth is limited
Solution Approach 1:
The patent combines digital phase shifter and analog phase shifter into a hybrid architecture. The digital phase shifter provides coarse phase adjustment with high resolution, while the analog phase shifter provides fine continuous phase adjustment. This merging allows the system to achieve high phase resolution without the excessive insertion loss and bandwidth limitations of purely digital phase shifters.
Solution Approach 2:
The phase shifting function is segmented into two parts: a digital phase shifter handling coarse quantized phase steps, and an analog phase shifter handling fine continuous phase adjustment. This segmentation allows each component to operate in its optimal range, achieving high overall resolution while maintaining low insertion loss and wide bandwidth through the analog portion.
2Ease of operation
If analog phase shifters are used to achieve continuous phase control, then phase continuity is improved, but temperature stability deteriorates due to phase variation over temperature
Solution Approach 1:
The patent incorporates temperature sensors that continuously monitor the operating temperature of the analog phase shifter. The measured temperature is fed back to a control system that dynamically adjusts the phase shift compensation in real-time, counteracting temperature-induced phase variations and maintaining stable phase performance across different operating conditions.
Solution Approach 2:
The system changes the control parameters of the analog phase shifter based on temperature conditions. By adjusting the phase shift amount as a function of temperature (using lookup tables or calibration data), the system compensates for temperature-dependent phase variations while maintaining continuous phase control capability.
3Measurement precision
If digital phase shifters with higher number of bits are used to achieve higher resolution, then phase resolution is improved, but bandwidth is limited and monotonic error occurs at certain frequencies
Solution Approach 1:
The hybrid architecture merges digital and analog phase shifters, where the digital portion provides high-resolution quantized control and the analog portion provides continuous adjustment capability. This combination achieves high phase resolution without requiring an excessively high-bit digital phase shifter, thereby maintaining wide bandwidth and avoiding monotonic errors that plague high-resolution purely digital designs.
4Ease of manufacture
If MMIC DPS using PHEMT technology is used for digital phase control, then integration is improved, but device complexity increases due to requirement of negative voltage for controlling
Solution Approach 1:
Instead of using complex negative voltage control circuits required by traditional MMIC digital phase shifters, the patent inverts the approach by using a microcontroller to generate digital control words that are converted to analog voltages through a DAC. This analog voltage directly controls the analog phase shifter, eliminating the need for complex negative voltage generation and switching networks, thereby reducing overall device complexity while maintaining integration.
Data Source
AI summary
Various embodiments of the invention relate to a high accuracy phase shift apparatus. The phase shift apparatus comprises a voltage controlled analog phase shifter, a microcontroller unit (MCU) and a digital-to-analog converter (DAC). The MCU generates a digital control signal, which is converted into an analog control signal by the DAC to control the voltage controlled analog phase shifter to achieve desired phase shift angle. The phase shift apparatus may further incorporate a temperature sensor for temperature compensation. The output from the temperature sensor may be used to modify the reference voltage of the DAC, or alternatively be used to modify the digital control signal from the MCU. By incorporation digitalized control and temperature compensation to an analog phase shifter, the disclosed phase shift apparatus achieves high accuracy digitalized control, a flat phase shift over a wide bandwidth, and a stable phase shift over temperature variation.