Current-Mode Vector Modulator Phase Shifters for Wideband Beamforming

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Solution Overview

Problem

Existing phase shifters in electronic systems, such as phased array antenna systems, face limitations in achieving wideband operation and accurate phase control, particularly in controlling parasitic capacitances and maintaining phase shifting over a full 360-degree range across all quadrants, which affects beamforming accuracy and frequency range.

Innovation Solution

The implementation of a phase shifter that includes a quadrature filter, in-phase and quadrature-phase variable gain amplifiers, and a current mode combiner, with gain settings controlled to generate differential I and Q components, allowing for precise phase shifting and wideband operation by reducing parasitic capacitances through current mode summing and calibration schemes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If traditional voltage mode combining is used to combine I and Q signal components, then the circuit implementation is simpler, but parasitic capacitances increase and bandwidth is limited

Engineering Contradiction:

Improvecircuit implementation simplicityVSAvoidoperational bandwidth

Core Design Contradiction:

Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The patent replaces voltage mode signal combining with current mode signal combining. This substitution transforms the signal processing domain from voltage to current, enabling wider bandwidth operation by reducing parasitic capacitance effects while maintaining circuit implementability through standard CMOS current mode techniques.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the fundamental operating parameter of the combiner from voltage mode to current mode. This parameter change fundamentally alters the impedance characteristics and parasitic behavior of the combining circuit, enabling wideband operation across the entire 360-degree phase range without the bandwidth limitations of traditional voltage mode approaches.

Inventive Principle:

Principle #35Parameter changes

2Measurement precision

If phase shifters are designed for accurate phase control, then beamforming accuracy improves, but the ability to maintain performance across all quadrants and wide frequency ranges is compromised

Engineering Contradiction:

Improvephase control accuracyVSAvoidfrequency range and quadrant coverage

Core Design Contradiction:

Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The patent designs a universal phase shifter architecture based on current mode vector modulation that functions accurately across all four quadrants of the 360-degree phase range and maintains performance over wide frequency ranges. The current mode combining approach provides multi-functional capability that traditional voltage mode designs cannot achieve simultaneously.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

By substituting voltage mode operation with current mode operation throughout the phase shifter architecture, the patent achieves both accurate phase control and wideband performance across all quadrants. The current mode approach eliminates the fundamental limitations that prevent simultaneous achievement of accuracy and versatility in traditional designs.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Ease of manufacture

If voltage mode combining is used for I and Q components, then the design is more conventional, but parasitic capacitances limit wideband operation

Engineering Contradiction:

Improvedesign conventionalityVSAvoidparasitic capacitances

Core Design Contradiction:

Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The patent substitutes voltage mode combining with current mode combining, which fundamentally changes how signals are processed and combined. This substitution dramatically reduces the impact of parasitic capacitances because current mode circuits are less sensitive to capacitive loading effects, enabling wideband operation while remaining implementable with standard semiconductor processes.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentUS11545950B2Apparatus and methods for vector modulator phase shifters

Publication Date: 2023.01.03 ANALOG DEVICES INC

AI summary

Apparatus and methods for vector modulator phase shifters are provided. In certain embodiments, a phase shifter includes a quadrature filter that filters a differential input signal to generate a differential in-phase (I) voltage and a differential quadrature-phase (Q) voltage, an in-phase variable gain amplifier (I-VGA) that amplifies the differential I voltage to generate a differential I current, a quadrature-phase variable gain amplifier (Q-VGA) that amplifies the differential Q voltage to generate a differential Q current, and a current mode combiner that combines the differential I voltage and the differential Q voltage to generate a differential output signal. A phase difference between the differential output signal and the differential input signal is controlled by gain settings of the I-VGA and the Q-VGA.