Integrated RF Module LNA Filter Spurious Leakage

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Solution Overview

Problem

Existing radio frequency modules face degradation in receiver sensitivity due to spurious components leaking from a first receive circuit into a second receive circuit during simultaneous transmission and reception of signals on multiple waves, particularly when frequencies overlap, leading to reduced performance and increased complexity.

Innovation Solution

The integration of a first filter circuit with a low noise amplifier (LNA) in the same package, utilizing a variable capacitor and a short stub configuration, effectively attenuates spurious components by reducing wiring length and insertion loss, and ensures electromagnetic field coupling is minimized, thereby isolating the receive circuits and preventing sensitivity degradation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a filter is disposed downstream of an LNA in separate modules, then filtering of spurious components is achieved, but spurious components may leak through wires and terminals before attenuation, degrading receiver sensitivity

Engineering Contradiction:

Improvereceiver sensitivityVSAvoidspurious component leakage

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent combines the LNA and filter circuit into a single integrated package, eliminating the physical separation that causes spurious component leakage through external wiring. The filter is directly coupled to the LNA output within the same package, preventing leakage paths through wire bonds and external terminals.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent introduces an intermediate coupling structure within the package that directly connects the LNA output to the filter input, serving as a controlled intermediary path that prevents spurious components from leaking through uncontrolled external wiring paths.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Loss of energy

If LNA and filter circuit are provided in the same package, then wiring length is reduced and insertion loss is decreased, but integration complexity increases

Engineering Contradiction:

Improveinsertion lossVSAvoidintegration complexity

Core Design Contradiction:

Loss of energyVSDevice complexity

Solution Approach 1:

The LNA and filter circuit are integrated into a single package with direct internal coupling, eliminating external wiring and reducing insertion loss. The integration is achieved through careful package design that combines multiple functional components while managing the increased complexity through systematic layout and coupling structures.

Inventive Principle:

Principle #5Merging (Combining)

3Productivity

If multiple receive circuits process signals in different frequency bands simultaneously, then high-capacity wireless communication is achieved, but spurious components from one circuit may interfere with another circuit

Engineering Contradiction:

Improvecommunication capacityVSAvoidinter-circuit interference

Core Design Contradiction:

ProductivityVSObject-generated harmful factors

Solution Approach 1:

The patent segments the receive circuits into separate frequency band processing paths, each with its own LNA and filter circuit. The first receive circuit processes signals in a first frequency band while the second receive circuit processes signals in a second frequency band, with each circuit having dedicated filtering to prevent spurious component interference with the other circuit.

Inventive Principle:

Principle #1Segmentation

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 configuration significantly reduces or prevents spurious component leakage, enhancing receiver sensitivity and allowing for a more compact, cost-effective design with adjustable filtering capabilities, even when signals from different frequency bands are processed simultaneously.

Implementation Method 1

a first filter circuit that is connected to an output end of the first low noise amplifier and that includes at least a first portion provided on the principal surface of the first substrate. The first filter circuit attenuates spurious components.

Methodology Applied

Scientific EffectElectromagnetic filtering: Filter (electronic)

Implementation Method 2

ensures electromagnetic field coupling is minimized, thereby isolating the receive circuits

Methodology Applied

Scientific EffectElectromagnetic isolation: Electromagnetic Induction

Data Source

PatentUS10797741B2Radio frequency module and communication device

Publication Date: 2020.10.06 MURATA MFG CO LTD

AI summary

A radio frequency module includes a first receive circuit that processes a receive signal in the first frequency band. The first receive circuit includes a first substrate, a first low noise amplifier, and a first filter circuit. The first low noise amplifier is mounted on a principal surface of the first substrate. The first filter circuit is connected to an output end of the first low noise amplifier. At least a portion of the first filter circuit is provided on the principal surface of the first substrate. The first filter circuit attenuates spurious components occurring due to a transmit signal in the first frequency band received by the first low noise amplifier. The spurious components are included in the transmit signal in the first frequency band and have a frequency bandwidth that overlaps, includes, or is included in the frequency bandwidth of the receive signal in the second frequency band.