Band Switch With Switchable Notch For Carrier Aggregation

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Solution Overview

Problem

Existing methods for reducing harmonic interference in wireless devices during receive carrier aggregation, such as adding static notch filters, introduce significant insertion losses and fail to adequately attenuate harmonics and distortion, impacting efficiency and talk time.

Innovation Solution

A band switch with a switchable notch filter that can be enabled or disabled using series and shunt switches, selectively coupled to attenuate signals within a stop band range of frequencies, reducing harmonic distortion without substantial insertion loss.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If static notch filters are added into the TX path to reduce harmonic interference, then receiver desensitization is reduced, but insertion losses significantly reduce efficiency

Engineering Contradiction:

Improvereceiver sensitivityVSAvoidinsertion loss

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The patent implements a switchable notch filter that can be dynamically enabled or disabled based on operational conditions. The notch filter is selectively activated when receive carrier aggregation is needed and the receive band coincides with the third harmonic of the transmit frequency, and disabled otherwise. This dynamic approach eliminates the need for continuously active static notch filters, thereby reducing insertion losses while maintaining receiver sensitivity when needed.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent changes the operational state of the notch filter from static (always on) to dynamic (conditionally on/off). By monitoring operational parameters such as the active transmit frequency and receive band, the system adjusts the notch filter's enable/disable state accordingly. This parameter-based control optimizes the balance between harmonic attenuation and insertion loss.

Inventive Principle:

Principle #35Parameter changes

2Object-generated harmful factors

If static notch filters are added to attenuate harmonics, then third harmonic distortion is reduced, but transmitter efficiency decreases due to continuous insertion loss

Engineering Contradiction:

Improvethird harmonic distortionVSAvoidtransmitter efficiency

Core Design Contradiction:

Object-generated harmful factorsVSUse of energy by moving object

Solution Approach 1:

The notch filter is implemented as a switchable component that is only activated when third harmonic distortion poses a problem. The system dynamically evaluates whether the receive band coincides with the third harmonic of the transmit frequency and enables the notch filter only in such conditions. This eliminates continuous energy loss from the filter while maintaining harmonic attenuation when necessary.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The notch filter operates periodically rather than continuously, being enabled only during specific operational windows when receive carrier aggregation is active and the third harmonic falls within the receive band. This periodic activation pattern reduces overall energy consumption and improves transmitter efficiency while still providing harmonic attenuation when needed.

Inventive Principle:

Principle #19Periodic action

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 achieves a reduction in insertion loss by up to 0.18 dB and provides effective attenuation of third harmonic distortion, improving transmitter efficiency and receiver sensitivity while maintaining efficiency.

Implementation Method 1

at least one notch filter is selectively coupled to the output in a shunt configuration, wherein the at least one notch filter is configured to attenuate signals within a stop band range of frequencies

Methodology Applied

Scientific EffectNotch filter attenuation: Filter (electronic)

Implementation Method 2

at least one series switch coupled between the at least one input and the output. The at least one series switch is adapted to selectively couple the at least one input to the output in response to a first control signal

Methodology Applied

Scientific EffectRF switching: Valve

Implementation Method 3

at least one shunt switch coupled between the at least one input and a voltage node. The voltage node is typically at ground potential, and the at least one shunt switch is adapted to selectively couple the at least input to the voltage node in response to a second control signal

Methodology Applied

Scientific EffectRF switching: Valve

Data Source

PatentUS9190699B2Band switch with switchable notch for receive carrier aggregation

Publication Date: 2015.11.17 QORVO US INC

AI summary

A band switch with a switchable notch for receive carrier aggregation is disclosed. The band switch has at least one input and an output with at least one series switch coupled between the at least one input and the output. The at least one series switch is adapted to selectively couple the input to the output in response to a first control signal. The band switch also includes at least one shunt switch coupled between the at least one input and a voltage node. The at least one shunt switch is adapted to selectively couple the at least one input to the voltage node in response to a second control signal. In addition, at least one notch filter is selectively coupled to the output in a shunt configuration, wherein the at least one notch filter is configured to attenuate signals within a stop band to attenuate harmonics and distortion.