Electroacoustic Filter Topology for Low Phase Delay Multiplexing

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Solution Overview

Problem

Current filters and multiplexers in multi-band communication systems face challenges in meeting performance thresholds, especially when additional frequency bands are added, leading to increased out-of-band dispersion and power leakage due to phase spread in the reflection coefficient, which affects device performance and space utilization.

Innovation Solution

The implementation of electroacoustic resonators with specific filter topologies that provide low phase delay filtering, using acoustic resonators, capacitors, and inductors to reduce interactions between frequency bands and improve multiplexing performance, allowing for efficient use of device resources and meeting communication standards.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If additional frequency bands are added to multi-band communication systems, then communication performance and frequency usage are improved, but out-of-band dispersion and power leakage increase due to phase spread in the reflection coefficient

Engineering Contradiction:

Improvefrequency band supportVSAvoidcommunication performance

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent changes the electrical length parameter of the transmission line to be less than 1/8 wavelength at the highest operating frequency. This parameter modification reduces phase spread across multiple frequency bands, thereby reducing out-of-band dispersion and power leakage while maintaining support for multiple frequency bands including LTE and 5G NR bands.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

Instead of allowing the transmission line to be electrically long (which would provide better impedance matching but cause phase spread), the patent inverts the approach by making the transmission line electrically short (less than 1/8 wavelength). This counterintuitive design choice prioritizes phase consistency across bands over traditional impedance matching considerations, resolving the contradiction between multi-band support and communication performance.

Inventive Principle:

Principle #13The other way round (Inversion)

2Reliability

If traditional RF filters are used for high-frequency signals, then filtering is achieved, but the filter device size becomes large

Engineering Contradiction:

Improvefiltering performanceVSAvoidfilter device size

Core Design Contradiction:

ReliabilityVSArea of stationary object

Solution Approach 1:

The patent replaces traditional mechanical/physical RF filter structures with an electroacoustic resonator-based solution. The electroacoustic resonator converts electrical signals to acoustic waves and back, enabling compact filtering at high frequencies (up to 8 GHz and beyond) without requiring large physical filter structures, thus maintaining filtering performance while reducing device size.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Area of stationary object

If acoustic resonators are used to reduce filter size, then device space is saved, but phase delay increases affecting multiplexed signals

Engineering Contradiction:

Improvefilter device sizeVSAvoidphase delay

Core Design Contradiction:

Area of stationary objectVSLoss of time

Solution Approach 1:

The patent modifies the electrical length parameter of the transmission line connecting to the electroacoustic resonator to be less than 1/8 wavelength. This parameter change reduces the phase delay introduced by the resonator structure, enabling the use of compact acoustic resonators while maintaining acceptable phase characteristics for multiplexed LTE and 5G NR signals.

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

This solution reduces out-of-band dispersion and improves communication performance by configuring low phase delay filters that effectively multiplex multiple frequency bands, enhancing device operation and meeting performance thresholds while maintaining or improving space utilization.

Implementation Method 1

Using a piezoelectric material as a vibrating medium, acoustic resonators operate by transforming an electrical signal wave that is propagating along an electrical conductor into an acoustic wave that is propagating via the piezoelectric material.

Methodology Applied

Scientific EffectPiezoelectric effect: Piezoelectric Effect

Data Source

PatentUS11990893B2Electroacoustic filter with low phase delay for multiplexed signals

Publication Date: 2024.05.21 RF360 SINGAPORE PTE LTD

AI summary

Aspects of the disclosure relate to wireless communication, and high-frequency filters with resonators configured to systematically modify phase characteristics of an antenna reflection coefficient. One aspect is a wireless communication apparatus comprising an acoustic resonator having a first resonator side and a second resonator side, the first resonator side coupled to a first signal connection port, a first capacitor including a first side coupled to the first resonator side and the first signal connection port, the first capacitor further including a second side coupled to a ground connection port, and a second capacitor including a first side coupled to the ground connection port, the second capacitor further including a second side, the second resonator side and the second side of the second capacitor coupled to an output port.