RF Front-End Amplifier with Negative Resistance for Carrier Aggregation

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Solution Overview

Problem

Conventional wireless receivers face challenges in intra-band carrier aggregation, particularly when processing signals requiring multiple local oscillator frequencies, leading to increased silicon area, power consumption, and performance degradation due to the need for multiple parallel LNAs and additional matching components.

Innovation Solution

A wireless receiver design that employs a single front-end amplifier with multiple processing chains, each operating with a different local oscillator frequency, and a negative resistor unit that applies negative resistance only when multiple chains are active to compensate for performance losses, thereby maintaining amplifier performance without significant power consumption increases.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If multiple parallel LNAs are used for intra-band carrier aggregation with multiple LO frequencies, then the receiver can process multiple frequency channels simultaneously, but the silicon area and power consumption increase significantly

Engineering Contradiction:

Improvemulti-frequency processing capabilityVSAvoidsilicon area

Core Design Contradiction:

Adaptability or versatilityVSArea of stationary object

Solution Approach 1:

The patent merges multiple LNA functions into a single shared front-end amplifier. This single amplifier serves multiple processing chains that operate with different local oscillator frequencies, eliminating the need for separate parallel LNAs for each frequency channel. The shared amplifier reduces silicon area while maintaining the capability to process multiple frequency channels simultaneously through the use of multiple processing chains with different LO frequencies.

Inventive Principle:

Principle #5Merging (Combining)

2Adaptability or versatility

If multiple parallel LNAs are used for intra-band carrier aggregation, then multiple frequency channels can be received simultaneously, but power consumption increases

Engineering Contradiction:

Improvemulti-frequency processing capabilityVSAvoidpower consumption

Core Design Contradiction:

Adaptability or versatilityVSUse of energy by stationary object

Solution Approach 1:

The patent combines multiple LNA functions into one shared front-end amplifier that serves multiple processing chains. This single amplifier consumes less power than multiple parallel LNAs would require, while still enabling simultaneous reception of multiple frequency channels through the multiple processing chains using different local oscillator frequencies.

Inventive Principle:

Principle #5Merging (Combining)

3Area of stationary object

If a single front-end amplifier is shared by multiple processing chains, then silicon area and power are reduced, but amplifier performance degrades due to loading effects

Engineering Contradiction:

Improvesilicon areaVSAvoidamplifier performance

Core Design Contradiction:

Area of stationary objectVSReliability

Solution Approach 1:

The patent introduces a negative resistance circuit as an intermediary element between the shared front-end amplifier and the multiple processing chains. This negative resistance circuit compensates for the loading effects caused by multiple parallel processing chains, thereby maintaining amplifier performance (gain, noise figure, input matching) while allowing the single amplifier to serve multiple frequency channels. The negative resistance effectively counteracts the parasitic effects introduced by the multiple chains.

Inventive Principle:

Principle #24Intermediary (Mediator)

4Use of energy by stationary object

If a single front-end amplifier is shared by multiple processing chains, then power consumption is reduced, but amplifier performance degrades

Engineering Contradiction:

Improvepower consumptionVSAvoidamplifier performance

Core Design Contradiction:

Use of energy by stationary objectVSReliability

Solution Approach 1:

The negative resistance circuit acts as a compensating intermediary that restores amplifier performance while keeping power consumption low. By placing this circuit between the shared amplifier and multiple processing chains, it counteracts the loading effects that would otherwise degrade gain, noise figure, and input matching, enabling the single amplifier to maintain high performance across multiple frequency channels without requiring multiple parallel amplifiers.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS8548410B2RF front-end for intra-band carrier aggregation

Publication Date: 2013.10.01 SNAPTRACK INC

AI summary

The method and apparatus described herein address problems associated with conventional wireless receivers configured for intra-band carrier aggregation. The disclosed solution applies the received signal to a single front-end amplifier, which may comprise a low-noise amplifier, and divides the amplified signal into two or more processing paths, where each path is associated with a different local oscillator frequency corresponding to a different reception band. To compensate for the impact of the additional processing paths on the amplifier performance, a negative resistor unit applies a negative resistance to the output of the front-end amplifier when two or more processing paths are active.