RF Input Matching Circuit Using One Inductor for Multi-Band LNAs

Solution Overview

Problem

In wireless transceivers, impedance matching for multiple RF frequency bands with a single external inductor is challenging, leading to increased signal loss and module size, as additional inductors are required for each band, which is undesirable.

Innovation Solution

A semiconductor device with a matching circuit incorporating a capacitor and switches, allowing for selective use of inductance and capacitance to configure parallel resonance circuits for impedance matching across multiple frequency bands without the need for additional external inductors, thereby reducing module size and signal loss.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If additional external inductors are added for each frequency band, then impedance matching for multiple bands is achieved, but module area increases

Engineering Contradiction:

Improveimpedance matching capabilityVSAvoidmodule area

Core Design Contradiction:

Adaptability or versatilityVSArea of stationary object

Solution Approach 1:

The patent combines multiple inductors into a single shared inductor that is common to all frequency bands. The inductor is placed in a signal path that is switched to different frequency bands, allowing one inductor to serve multiple impedance matching functions that would traditionally require separate inductors for each band.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The single inductor is designed to perform multiple functions by being shared across different frequency bands. Through the switching mechanism, the same inductor provides impedance matching for multiple bands, making it a universal component that replaces what would traditionally require multiple band-specific inductors.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Adaptability or versatility

If additional external inductors are added for each frequency band, then impedance matching for multiple bands is achieved, but signal loss increases

Engineering Contradiction:

Improveimpedance matching capabilityVSAvoidsignal loss

Core Design Contradiction:

Adaptability or versatilityVSLoss of energy

Solution Approach 1:

The patent combines multiple inductors into a single shared inductor that is common to all frequency bands. The inductor is placed in a signal path that is switched to different frequency bands, allowing one inductor to serve multiple impedance matching functions that would traditionally require separate inductors for each band.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent converts what would traditionally be a limitation (using a single inductor for multiple bands) into a benefit by reducing the total number of inductors, thereby reducing cumulative signal loss while maintaining impedance matching capability across all bands through intelligent switching.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Area of stationary object

If a single external inductor is used for multiple frequency bands, then module area is reduced, but impedance matching performance deteriorates

Engineering Contradiction:

Improvemodule areaVSAvoidimpedance matching capability

Core Design Contradiction:

Area of stationary objectVSAdaptability or versatility

Solution Approach 1:

The patent introduces dynamic switching between different signal paths that include the shared inductor. The switching mechanism allows the system to adaptively select the appropriate impedance matching configuration for each frequency band, making the single inductor system dynamically adjustable rather than static.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The switching mechanism acts as an intermediary that enables the single inductor to effectively serve multiple frequency bands. The switch routes signals through the inductor in different configurations depending on the active frequency band, mediating between the single inductor resource and multiple band requirements.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 solution enables efficient impedance matching across multiple frequency bands without increasing the receiver module's area, achieving performance comparable to conventional methods using additional inductors while minimizing signal loss.

Implementation Method 1

A semiconductor device with a matching circuit incorporating a capacitor and switches, allowing for selective use of inductance and capacitance to configure parallel resonance circuits for impedance matching

Methodology Applied

Scientific EffectParallel resonance: Resonance

Data Source

PatentUS11277158B2Semiconductor device

Publication Date: 2022.03.15 KK TOSHIBA

AI summary

According to one embodiment, a semiconductor device includes: a selector configured to select one of multiple input terminals and to connect the selected input terminal to a connection terminal connected to one end of an inductor; a low noise amplifier in which an input terminal is connected to a connection terminal connected to the other end of the inductor; and at least one matching circuit. The matching circuit is connected between the two connection terminals and includes a first switch, a second switch, and a capacitor, one end of the capacitor is connected to one of the two connection terminals via the first switch, and the other end of the capacitor is connected to the other of the two connection terminals via the second switch.