RF Phase Shift Apparatus Using Coupled Transmission Lines

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Solution Overview

Problem

Existing phase shift circuitry for wireless devices fails to provide a substantially constant phase shift over a wide frequency band, limiting its effectiveness in mitigating multipath signal interference and adhering to wireless signal technology standards.

Innovation Solution

The use of mutually dissimilar and electrically coupled electromagnetic transmission line patterns on opposing sides of a substrate, with one side featuring a microstrip structure and the other a patch-slot structure, allows for selective phase shifts of 90 degrees or more over a wide frequency band, maintaining phase consistency across 800 MHz to 8 GHz with minimal insertion loss.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a transmission line of selected length is used to achieve a desired phase shift, then the phase shift requirement is met, but the bandwidth over which this phase shift remains effective is very narrow

Engineering Contradiction:

Improvephase shift accuracyVSAvoidbandwidth

Core Design Contradiction:

Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The transmission line is divided into multiple sections with different electrical lengths and characteristic impedances. Each section contributes a portion of the total phase shift, allowing the overall phase shift to remain constant across a wider bandwidth than a single transmission line could provide.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent varies the electrical length and characteristic impedance parameters across different transmission line sections. By carefully selecting these parameters, the phase shift remains substantially constant over a wide frequency range, resolving the contradiction between phase accuracy and bandwidth.

Inventive Principle:

Principle #35Parameter changes

2Adaptability or versatility

If tight signal coupling between transmission line elements is used to increase bandwidth, then wider bandwidth is achieved, but implementation becomes difficult

Engineering Contradiction:

ImprovebandwidthVSAvoidimplementation difficulty

Core Design Contradiction:

Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The patent introduces intermediate coupling structures between transmission line elements that provide controlled signal coupling without requiring tight coupling. These intermediaries facilitate wider bandwidth operation while maintaining ease of implementation through standard manufacturing techniques.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Adaptability or versatility

If multiple phase shifters are used to provide selectable phase shifts over wide bandwidth, then phase shift versatility is improved, but device complexity increases

Engineering Contradiction:

Improvephase shift selectabilityVSAvoidnumber of phase shifters

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent designs a universal phase shifter structure that can provide multiple selectable phase shift values (e.g., 0°, 45°, 90°, 135°, 180°) through a single device configuration. This multi-functional approach eliminates the need for multiple separate phase shifters, reducing overall device complexity while maintaining phase shift versatility.

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

This solution enables phase shifts of up to 90 degrees with a variance of ±20 degrees over a wide frequency range, reducing the need for multiple phase shifters and ensuring compliance with wireless standards while minimizing interference.

Implementation Method 1

a first electromagnetic transmission line pattern with mutually dissimilar and electrically coupled first and second pattern portions electrically coupled between first and second signal terminals; and a second electromagnetic transmission line pattern for electromagnetic communication with the second pattern portion

Methodology Applied

Scientific EffectElectromagnetic coupling: Electromagnetic Induction

Data Source

PatentUS9306257B2RF phase shift apparatus having an electrically coupled path separated from an electromagnetically coupled path to provide a substantially constant phase difference therebetween

Publication Date: 2016.04.05 LITEPOINT CORP

AI summary

Circuitry for shifting a phase of a radio frequency (RF) signal. Mutually dissimilar and electrically coupled portions of an electromagnetic transmission line pattern on one side of a substrate interact with another electromagnetic transmission line pattern on the opposing substrate side to convey a RF signal with a phase shift that is determined by the RF signal frequency and respective dimensions of the electromagnetic transmission line patterns and is substantially constant over a wide bandwidth. With multiple implementations of such opposing electromagnetic transmission line patterns having different pattern dimensions and coupled between RF signal switches, multiple phase shifts can be selectively provided.