Bridge Phase Shifter Topology for 360° Range With Low Insertion Loss
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Solution Overview
Problem
Current phase shifters in nuclear magnetic resonance imaging (MRI) technology have limited phase shift range and high insertion loss, which affects system gain and noise, and are difficult to achieve a phase shift of 180 degrees.
Innovation Solution
A phase shifter with a bridge and two 4-way switches that can selectively switch between capacitance, inductance, open circuit, and short circuit under control voltage, allowing for continuous phase shift from 0 to 360 degrees, reducing insertion loss and enabling precise control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a conventional phase shifter with diodes and capacitances is used, then the phase shift function is achieved, but the phase shift range is too small (about 26 degrees) and insertion loss is large
Solution Approach 1:
The phase shifter is divided into multiple independent phase shift units, each capable of providing a specific phase shift range. By segmenting the overall phase shift requirement into multiple smaller units that can be combined, the patent achieves a total phase shift range of 0-360 degrees while maintaining low insertion loss in each segment.
Solution Approach 2:
Multiple phase shift units are nested or cascaded together, where each unit contributes to the overall phase shift. The first phase shift unit provides a baseline phase shift, and subsequent units add additional phase shift capability, creating a nested structure that accumulates phase shift while managing insertion loss.
2Reliability
If feedback, feed forward or predistortion technology is used to enhance ACPR and improve power amplifier linearity, then the linearity is improved, but the device complexity increases
Solution Approach 1:
The phase shifter serves as an intermediary component that enables power amplifier linearity improvement through phase manipulation. By providing precise phase control capability (0-360 degrees), the phase shifter facilitates feedback and predistortion techniques without requiring complex additional circuitry, as the phase control is integrated into the signal path.
3Adaptability or versatility
If a phase shifter with broader phase shift range is used, then more phase values are available, but it is difficult to realize a phase shift of 180 degrees
Solution Approach 1:
The phase shifter employs dynamic control mechanisms where the phase shift amount can be continuously or discretely adjusted across the full 0-360 degree range. This dynamic capability allows precise achievement of specific phase values like 180 degrees by controlling the phase shift units, while maintaining the ability to operate at any phase value within the range.
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 provides a phase shifter with a wide range of phase shift (0-360 degrees) and low insertion loss, improving system gain, reducing noise, and preventing self-excitation in power amplifiers, while being easy to control and use.
Implementation Method 1
The two 4-way switches are designed to selectively switch on one of a capacitance, an inductance, an open circuit, and a short circuit under the control of a control voltage
Implementation Method 2
The two 4-way switches are designed to selectively switch on one of a capacitance, an inductance, an open circuit, and a short circuit under the control of a control voltage
Implementation Method 3
The impedance of the diode 8 and diode 9 will vary with the changes of the bias voltage. The changes of the impedances of the diode 8 and diode 9 inevitably cause phase variation from the output port Pout to the input port Pin
Data Source
AI summary
A phase shifter is provided. The phase shifter includes a first phase shifter that is continuously adjustable within a range of 0 degrees to 90 degrees, two 4-way switches each configured to selectively switch on one of a capacitance, an inductance, an open circuit, and a short circuit under control of a control voltage, and a bridge. A first input end and a first output end of said bridge are respectively connected to a first 4-way switch of the two 4-way switches. A second input end of said bridge is connected to an output end of said first phase shifter or a second output end of said bridge is connected to an input end of said first phase shifter.