Additively Printed RC Pass Filter for Wide RF Stopband Rejection

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Solution Overview

Problem

Conventional low pass filters for RF circuits face challenges in achieving a wide stopband rejection, high linearity, and compact size while maintaining low cost, particularly in high RF frequency ranges, due to limitations in stepped impedance, open stub, and defected ground structure implementations.

Innovation Solution

The use of additive manufacturing (AM) systems for simultaneous deposition of conductive and dielectric inks to fabricate passive RC frequency pass filters, which include a plurality of resistors and capacitors configured to provide a predetermined cutoff frequency and wide stopband rejection, using ink jet printing with a computer-aided manufacturing module to control the deposition process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If stepped impedance low pass filters or open stub low pass filters are used, then the filter can be implemented with simple structure, but the cut-off response becomes gradual and stopband rejection is insufficient

Engineering Contradiction:

Improvefilter implementation simplicityVSAvoidstopband rejection

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The filter is divided into multiple sections (e.g., five sections) with alternating high and low impedance transmission lines. Each section contributes to the overall frequency response, creating a steeper cut-off and wider stopband through cumulative effect rather than relying on a single complex structure.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The characteristic impedance values are specifically optimized (e.g., Z0H = 120Ω, Z0L = 60Ω) to achieve the desired frequency response. By adjusting impedance parameters and physical dimensions (width, length) of each section, the filter achieves sharp cut-off and wide stopband rejection.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If the number of sections in stepped impedance low pass filter is increased to improve rejection characteristics, then the stopband rejection improves, but the passband insertion loss increases and physical dimensions increase

Engineering Contradiction:

Improverejection characteristicsVSAvoidphysical dimensions

Core Design Contradiction:

ReliabilityVSLength of moving object

Solution Approach 1:

The filter transitions from planar 2D layout to 3D vertical stacking with multiple layers. This allows multiple filter sections to be arranged in three-dimensional space, achieving compact size while maintaining the required number of sections for sharp cut-off and wide stopband rejection.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

Multiple filter sections are nested within each other through vertical stacking, where each layer contains filter elements that are coupled through vias. This nesting approach allows compact integration of multiple sections without increasing planar footprint.

Inventive Principle:

Principle #7Nested doll (Nesting)

3Reliability

If defected ground structure microstrip line is used to implement wide stopband, then the stopband width increases, but radiation increases and metallic enclosure is required

Engineering Contradiction:

Improvestopband widthVSAvoidradiation

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The filter uses composite structure combining high and low impedance transmission lines with specific dielectric materials. This composite approach achieves wide stopband rejection through controlled impedance transitions and resonant effects without requiring defective ground structures that cause radiation.

Inventive Principle:

Principle #40Composite materials

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 AM-fabricated RC filters achieve a steep rolloff rate, low insertion loss, and wide stopband rejection, enabling improved performance and cost-effectiveness in RF circuits, with options for unshielded and shielded configurations suitable for various frequency ranges.

Implementation Method 1

using ink jet printing with a computer-aided manufacturing module to control the deposition process

Methodology Applied

Scientific EffectInk jet deposition:

Implementation Method 2

providing an ink jet printing system comprising: a first print head, sized and configured to dispense a dielectric ink composition

Methodology Applied

Scientific EffectDielectric deposition: Dielectric

Implementation Method 3

a second print head sized and configured to dispense a conductive ink composition

Methodology Applied

Scientific EffectConductive ink deposition: Conduction (electrical)

Data Source

PatentUS12133336B2Systems and methods for additive manufacturing passive resistor-capacitor frequency pass filter (PRC FPF)

Publication Date: 2024.10.29 NANO DIMENSIONS TECH LTD

AI summary

The disclosure relates to systems and methods for fabricating passive RC frequency filter. More specifically, the disclosure is directed to computerized systems and methods for using additive manufacturing (AM) of simultaneous deposition of conductive and dielectric inks to form passive RC frequency pass filters having predetermined cutoff frequency with wide stop band frequency.