Passive Vector Modulator Phase Shifter for Wideband Phased Arrays
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Solution Overview
Problem
Existing passive phase shifters in phased array systems face limitations such as narrow bandwidth, high insertion loss, and large chip area requirements, while active phase shifters have high power consumption, low linearity, and high noise.
Innovation Solution
A passive wideband vector modulator phase shifter design incorporating an In-phase and Quadrature (IQ) signal generator, a combined signal attenuator and sign flip module, and a signal combiner, which provides good linearity over a wide frequency range and can be implemented in a compact form, suitable for large arrays.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If passive phase shifters are used, then linearity and noise performance are improved, but bandwidth is reduced and insertion loss increases
Solution Approach 1:
The phase shifter is divided into multiple independent unit cells (e.g., four unit cells) that can be independently controlled. Each unit cell contributes a specific phase shift (0°, 90°, 180°, 270°), and their combination enables continuous phase control across a wide bandwidth while maintaining passive topology for good linearity and low noise.
Solution Approach 2:
The phase shifter uses dynamic switching mechanisms (such as PIN diodes or MOSFETs) to reconfigure the impedance of each unit cell, enabling continuous phase adjustment from 0° to 360° without changing the physical structure. This dynamic reconfiguration allows wideband operation while maintaining passive characteristics.
2Use of energy by moving object
If passive phase shifters are used, then power consumption is reduced, but bandwidth is reduced and chip area increases
Solution Approach 1:
The phase shifter is divided into multiple independent unit cells (e.g., four unit cells) that can be independently controlled. Each unit cell contributes a specific phase shift (0°, 90°, 180°, 270°), and their combination enables continuous phase control across a wide bandwidth while maintaining passive topology for good linearity and low noise.
Solution Approach 2:
The design changes the impedance parameters of each unit cell dynamically through switching elements, enabling the same passive structure to achieve different phase shifts across a wide frequency range. This parameter modulation allows wideband operation without active components.
3Use of energy by moving object
If reflective-type passive phase shifters are used, then power consumption is reduced, but phase response exhibits ripples and bandwidth is reduced
Solution Approach 1:
The phase shifter is divided into multiple independent unit cells (e.g., four unit cells) that can be independently controlled. Each unit cell contributes a specific phase shift (0°, 90°, 180°, 270°), and their combination enables continuous phase control across a wide bandwidth while maintaining passive topology for good linearity and low noise.
Solution Approach 2:
The patent introduces intermediate transmission lines and impedance transformation networks between the reflective elements and the signal path. These intermediaries smooth out the phase ripples by distributing the phase shift across multiple stages, resulting in a more linear phase response across the bandwidth.
Data Source
AI summary
Methods and apparatus for implementing passive wideband phase shifters are described. The phase shifters exhibit good linearity over a wide range of frequencies. Furthermore at least some features are directed to allowing the phase shifters to be implemented in some embodiments in a relatively compact manner making such embodiments well suited for supporting arrays and/or other implementations where a large number of phase shifters are to be implemented in a relatively small chip area.