Bi-Directional mmWave CMOS Phase Shifter With Low-Loss Fine Steps
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current phase shifter designs for 5G mmWave frequencies face challenges in achieving precise phase shift steps with low insertion loss, particularly in implementing 2.8 degrees and 5.6 degrees control steps, which are essential for beamforming and beam steering, and are not adaptable to various fabrication technologies like CMOS and SOI.
Innovation Solution
The development of passive, bi-directional, two-step phase shifters with a triple inductor network and a resistance switch network that allows for 2.8 degrees and 5.6 degrees phase shifts with low insertion loss, utilizing a center inductor and peripheral inductors electromagnetically coupled, along with resistor networks and transistor switches for digital control, enabling operation in mmWave frequencies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional phase shifter designs are used for 5G mmWave frequencies, then beamforming capability is achieved, but insertion loss increases and manufacturing adaptability decreases
Solution Approach 1:
The phase shifter design uses standard CMOS-compatible passive components (inductors, resistors, capacitors) and transistor switches that can be manufactured using conventional CMOS and SOI fabrication processes. The circuit topology is universally applicable across different fabrication technologies, enabling the same design to be produced in various process nodes without requiring technology-specific modifications.
Solution Approach 2:
The patent employs continuous variable phase shift control by adjusting the resistance values in the resistive divider network, which changes the phase shift parameter continuously rather than in discrete steps. This parameter adjustment approach allows optimization of insertion loss while maintaining compatibility with standard fabrication processes.
2Measurement precision
If precise phase shift steps (2.8 degrees and 5.6 degrees) are implemented, then beamforming precision is improved, but device complexity increases
Solution Approach 1:
The phase shifter uses dynamically controllable transistor switches that can be programmed to achieve precise phase shift steps of 2.8 degrees and 5.6 degrees. The dynamic switching of transistor pairs allows precise phase control without requiring complex fixed circuitry for each phase step, reducing overall device complexity while maintaining high precision.
Solution Approach 2:
The phase shifter circuit is divided into multiple identical unit cells, each contributing a specific phase shift. By segmenting the total phase shift into smaller incremental steps achieved by individual unit cells, the design achieves precise 2.8度和5.6度 phase steps through modular repetition rather than requiring a completely complex custom circuit for each precision level.
3Loss of energy
If passive components are used for low loss, then insertion loss is reduced, but adaptability to digital control decreases
Solution Approach 1:
The patent replaces traditional mechanical or analog control mechanisms with digital control using transistor switches. The passive RF components (inductors, resistors, capacitors) maintain low insertion loss, while digital control signals switch transistor pairs to select different phase shift values. This substitution enables precise digital control of passive components without degrading their low-loss performance.
Solution Approach 2:
Transistor switches act as intermediaries between the digital control domain and the passive RF components. The digital control signals activate or deactivate specific transistor pairs, which in turn connect different passive component configurations to achieve the desired phase shift. This intermediary approach allows digital control of passive components while maintaining their inherent low-loss characteristics.
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 proposed phase shifters achieve precise phase shifts with minimal insertion loss and are adaptable to different fabrication technologies, suitable for 5G beamformers, offering high tolerance and minimal variation over a wide frequency range, with potential for implementation in CMOS processes.
Implementation Method 1
a triple inductor network and a resistance switch network that allows for 2.8 degrees and 5.6 degrees phase shifts with low insertion loss, utilizing a center inductor and peripheral inductors electromagnetically coupled
Data Source
AI summary
A phase shifter with a first port and a second port has a triple inductor network with a center inductor connected to the first port and the second port, and first and second peripheral inductors each electromagnetically coupled to the center inductor. A resistance switch network that is connected to the first and second peripheral inductors. The resistance switch network is selectively activatable to set a first state defined at least by a first resistance in a series circuit with the first and second peripheral inductors, a second state defined at least by a second resistance in the series circuit, and a third state defined at least by a third resistance in the series circuit. A transmission signal from the first port to the second port is shifted in phase by a prescribed angle corresponding to forward transmission coefficients for the first state, second state, and third state.