3D Electrically Tunable RF Phase Shifter with Dual Material Biasing

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Solution Overview

Problem

Conventional tunable RF phase shifters face limitations such as low operating frequency, impedance mismatch, and integration issues due to the use of ferromagnetic and ferrite materials, which restrict their tuning range and design flexibility, and often require external biasing magnetic fields.

Innovation Solution

A compact 3-D electrically tunable phase shifter utilizing both ferromagnetic and ferroelectric materials, specifically Permalloy and PZT, with dual tunability through inductive and capacitive means, allowing phase tuning over a wide range without changing the characteristic impedance, achieved by applying DC current and voltage without additional biasing networks.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If ferromagnetic and ferrite materials are used for tunable phase shifter, then phase tuning capability is achieved, but operating frequency is limited below 1 GHz and impedance mismatch occurs

Engineering Contradiction:

Improvephase tuning capabilityVSAvoidoperating frequency

Core Design Contradiction:

Adaptability or versatilityVSSpeed

Solution Approach 1:

The patent employs a composite structure combining ferromagnetic material (for phase tuning) with a transmission line structure. This allows the ferromagnetic material to provide phase variability while the transmission line maintains impedance matching and enables higher operating frequencies beyond 1 GHz, resolving the contradiction between phase tuning capability and operating frequency limitation

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent changes the operating parameters by using DC bias current to control the permeability of ferromagnetic material, thereby tuning the phase shift. By optimizing the bias current range and transmission line parameters, the system achieves both phase tuning capability and extended operating frequency range while maintaining impedance matching

Inventive Principle:

Principle #35Parameter changes

2Adaptability or versatility

If ferromagnetic materials are used as substrate, then phase tuning is achieved, but external biasing magnetic field is required causing integration issues

Engineering Contradiction:

Improvephase tuningVSAvoidbiasing network

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent replaces the mechanical/external biasing magnetic field system with an electrical biasing system. DC bias current is applied through the transmission line structure to control the ferromagnetic material's permeability, eliminating the need for external magnetic field generators and complex biasing networks, thereby simplifying integration

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The transmission line structure serves as an intermediary that carries both the RF signal and the DC bias current. This intermediary structure enables electrical control of the ferromagnetic material without requiring separate external biasing equipment, reducing device complexity while maintaining phase tuning capability

Inventive Principle:

Principle #24Intermediary (Mediator)

3Adaptability or versatility

If inductive tuning is used, then phase variation is achieved, but characteristic impedance changes causing impedance mismatch

Engineering Contradiction:

Improvephase variationVSAvoidcharacteristic impedance

Core Design Contradiction:

Adaptability or versatilityVSStability of the object's composition

Solution Approach 1:

The patent carefully controls the change parameters of the ferromagnetic material by optimizing the DC bias current range. By limiting the permeability variation to a specific range, the phase shift is tuned while the characteristic impedance remains relatively stable, avoiding significant impedance mismatch

Inventive Principle:

Principle #35Parameter changes

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 continuous tunability with low response time, increased phase tuning range, and constant impedance, suitable for high-frequency applications like 5G wireless communication, and eliminates the need for external biasing, enhancing design flexibility and reliability.

Implementation Method 1

The phase variation can be obtained by tuning the permeability of the substrate

Methodology Applied

Scientific EffectFerromagnetism: Ferromagnetism

Implementation Method 2

A compact 3-D electrically tunable phase shifter utilizing both ferromagnetic and ferroelectric materials

Methodology Applied

Scientific EffectFerroelectricity: Dielectric Permittivity

Data Source

PatentUS20230207998A1Dually Electrically Tunable 3-D Compact RF Phase Shifter

Publication Date: 2023.06.29 UNIVERSITY OF SOUTH CAROLINA

AI summary

An electrically tunable radio frequency phase shifter with compact 3-D structure that integrates both ferromagnetic and ferroelectric materials, and utilizes 3-D structure to increase the tuning efficiency and achieve miniaturization.