LC Resonator Time Delay Filter for Low-Loss Transceivers

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Solution Overview

Problem

Traditional time delay elements in analog circuits, such as RF transceivers, face limitations due to excessive size, cost, complexity, poor manufacturability, high loss, and high amplitude or phase ripple, which hinder their performance.

Innovation Solution

The development of a time delay filter system utilizing LC resonators with integrated intra-filter coupling and input matching elements, constructed on a laminate or semiconductor substrate, providing a frequency-invariant group delay with low insertion loss and adjustable impedance, enabling high accuracy and reconfigurability without increasing circuit complexity or cost.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of time

If traditional delay elements (ceramic filters, SAW filters, coaxial cables) are used, then time delay function is achieved, but size becomes excessive

Engineering Contradiction:
Improvetime delayVSAvoidsize
Core Design Contradiction:
Loss of timeVSVolume of moving object

Solution Approach 1:

The patent replaces traditional mechanical/physical delay elements (ceramic filters, SAW filters, coaxial cables) with an electronic circuit implementation using LC resonators. This substitution transitions from bulky physical structures to compact electronic components, achieving the same time delay function with significantly reduced size.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent achieves time delay by adjusting electrical parameters (inductance L and capacitance C values) of the LC resonators rather than relying on fixed physical dimensions. By changing these electrical parameters, the delay characteristics can be optimized without increasing physical size.

Inventive Principle:
Principle #35Parameter changes

2Loss of time

If traditional delay elements are used, then time delay function is achieved, but cost becomes excessive

Engineering Contradiction:
Improvetime delayVSAvoidcost
Core Design Contradiction:
Loss of timeVSEase of manufacture

Solution Approach 1:

The patent employs inexpensive LC resonator components that can be easily manufactured and replaced if needed, replacing costly traditional delay elements. The use of standard inductors and capacitors in an integrated circuit approach reduces overall system cost.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

By substituting expensive traditional delay elements with a custom-designed electronic circuit using readily available LC components, the patent significantly reduces manufacturing cost while maintaining the time delay function.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Loss of time

If traditional delay elements are used, then time delay function is achieved, but device complexity increases

Engineering Contradiction:
Improvetime delayVSAvoidcomplexity
Core Design Contradiction:
Loss of timeVSDevice complexity

Solution Approach 1:

The patent combines multiple LC resonators into a single integrated circuit architecture, merging their functions to achieve the desired time delay. This consolidation reduces overall device complexity compared to using separate traditional delay elements.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The LC resonator circuit is designed to perform multiple functions (time delay, filtering, impedance matching) within a single integrated structure, reducing the need for additional separate components and thereby simplifying the overall device complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

4Loss of time

If traditional delay elements are used, then time delay function is achieved, but insertion loss becomes high

Engineering Contradiction:
Improvetime delayVSAvoidinsertion loss
Core Design Contradiction:
Loss of timeVSLoss of energy

Solution Approach 1:

The patent optimizes the L and C parameter values of the resonators to minimize energy loss. By carefully selecting and tuning these parameters, the circuit achieves low insertion loss while maintaining the required time delay characteristics.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The LC resonators operate at their resonant frequencies, exploiting resonance to minimize energy dissipation. This resonant operation allows the circuit to achieve the time delay function with minimal insertion loss.

Inventive Principle:
Principle #18Mechanical vibration

5Loss of time

If traditional delay elements are used, then time delay function is achieved, but amplitude ripple becomes high

Engineering Contradiction:
Improvetime delayVSAvoidamplitude ripple
Core Design Contradiction:
Loss of timeVSStability of the object's composition

Solution Approach 1:

The patent combines multiple LC resonators in a coordinated manner, where their combined frequency responses smooth out individual resonances. This merging effect reduces amplitude ripple in the overall frequency response while maintaining the time delay function.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

By adjusting the L and C parameters of individual resonators, the patent optimizes their frequency responses to complement each other, thereby minimizing amplitude ripple across the operating bandwidth while preserving the desired time delay characteristics.

Inventive Principle:
Principle #35Parameter changes

6Loss of time

If traditional delay elements are used, then time delay function is achieved, but phase ripple becomes high

Engineering Contradiction:
Improvetime delayVSAvoidphase ripple
Core Design Contradiction:
Loss of timeVSStability of the object's composition

Solution Approach 1:

The patent carefully selects and tunes the L and C parameters of the resonators to achieve linear phase response characteristics. By optimizing these parameters, the circuit minimizes phase ripple while maintaining the required time delay, ensuring stable signal transmission.

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 enhances the performance of full-duplex transceivers and other systems by providing high accuracy, adjustable, and reconfigurable time delay filtering with reduced size and cost, while maintaining low insertion loss and minimizing amplitude and phase ripple.

Implementation Method 1

A time delay filter system may include one or more LC resonators

Methodology Applied
Scientific EffectLC resonance: Resonance

Implementation Method 2

The resonator may include a capacitive element and an inductive element, coupled together into an LC circuit

Methodology Applied
Scientific EffectElectromagnetic energy storage: Capacitance

Data Source

PatentEP3391459B1Time delay filters
Publication Date: 2022.06.15 KUMU NETWORKS INC
  • EP3391459B1 patent drawingFigure 1A~1B
  • EP3391459B1 patent drawingFigure 2A~2B
  • EP3391459B1 patent drawingFigure 3

AI summary

A time delay filter comprising a substrate comprising a first surface and a second surface opposite the first surface; a first LC resonator coupled to the substrate and comprising a first coupling point, a first capacitive element electrically coupled between the first coupling point and the first conductive region, and a first inductive element coupled between the first coupling point and the first conductive region, and comprising a first and second inductor tap; and a second LC resonator coupled to the substrate and comprising a second coupling point, a second capacitive element electrically coupled between the second coupling point and the first conductive region, and a second inductive element electrically coupled between the second coupling point and the first conductive region wherein the system group delays a signal output at a second coupling point relative to a signal input at the first coupling point.