Phase Shifter With Impedance Adjustment Circuit

Solution Overview

Problem

Existing phase shifters in high-frequency circuits fail to provide independent phase-shift operations for multiple frequency bands, leading to interference between filters and inadequate impedance matching, especially in communication terminal apparatuses.

Innovation Solution

A phase shifter with a transformer having magnetically coupled coils and an impedance adjustment circuit, featuring a reactance element to suppress parasitic inductance effects, allowing for controlled phase-shift amounts across frequency bands, thereby reducing interference and enhancing impedance matching.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a high-pass-filter-type phase shifter is used to shift phase in the low band, then the phase-shift amount in the low band can be 90°, but the phase-shift amount in the high band becomes 30° instead of 0°, causing interference

Engineering Contradiction:

Improvephase-shift amount controlVSAvoidinterference between filters

Core Design Contradiction:

Measurement precisionVSObject-generated harmful factors

Solution Approach 1:

The phase shifter is divided into multiple independent sections, each responsible for a specific frequency band. The low-band section and high-band section are separately designed and connected in series, allowing independent phase-shift control for each band without mutual interference.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different sections of the phase shifter are designed with different electrical characteristics tailored to specific frequency bands. The low-band section has parameters optimized for low-frequency operation, while the high-band section has parameters optimized for high-frequency operation, enabling each section to perform its function independently.

Inventive Principle:

Principle #3Local quality

2Measurement precision

If a low-pass-filter-type phase shifter is used to shift phase in the low band, then the phase-shift amount in the low band can be -90°, but the phase-shift amount in the high band becomes 100° instead of 180°, causing inadequate impedance matching

Engineering Contradiction:

Improvephase-shift amount controlVSAvoidimpedance matching performance

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The phase shifter is divided into multiple independent sections, each responsible for a specific frequency band. The low-band section and high-band section are separately designed and connected in series, allowing independent phase-shift control for each band without mutual interference.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different sections of the phase shifter are designed with different electrical characteristics tailored to specific frequency bands. The low-band section has parameters optimized for low-frequency operation, while the high-band section has parameters optimized for high-frequency operation, enabling each section to perform its function independently.

Inventive Principle:

Principle #3Local quality

3Device complexity

If a single phase shifter design is used for both low band and high band, then the device complexity is reduced, but the phase-shift characteristic cannot be controlled independently for each frequency band

Engineering Contradiction:

Improvephase shifter structureVSAvoidfrequency band adaptability

Core Design Contradiction:

Device complexityVSAdaptability or versatility

Solution Approach 1:

The phase shifter is divided into multiple independent sections, each responsible for a specific frequency band. The low-band section and high-band section are separately designed and connected in series, allowing independent phase-shift control for each band without mutual interference.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The phase shifter is designed to perform multiple functions by handling different frequency bands independently. Each section can be optimized for its specific band while the overall device maintains a unified structure, achieving both simplicity and multi-functionality.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 enables precise phase shifting and impedance matching across frequency bands, reducing interference between filters and maintaining isolation, thus improving the performance of communication terminal apparatuses.

Implementation Method 1

a transformer connected between a first port and a second port and including a first coil and a second coil that is magnetically coupled to the first coil

Methodology Applied

Scientific EffectMagnetic coupling: Electromagnetic Induction

Data Source

PatentUS10079587B2Phase shifter, impedance matching circuit, multi/demultiplexer, and communication terminal apparatus

Publication Date: 2018.09.18 MURATA MFG CO LTD

AI summary

A phase shifter includes a transformer connected between a first port and a second port and including a first coil and a second coil that is magnetically coupled to the first coil, the transformer including a parasitic inductance component; and an impedance adjustment circuit including a reactance element that suppresses a deviation in impedance due to the parasitic inductance component of the transformer. A coupling coefficient between the first coil and the second coil of the transformer and a value of the reactance element of the impedance adjustment circuit are determined such that a phase-shift amount changes in accordance with a frequency band.