Adaptive RF Front-End Tuning for Impedance Mismatch

Solution Overview

Problem

Modern mobile handsets face performance degradation in RF front-end antennas due to impedance mismatch and the complexity of supporting multiple frequency bands and standards, leading to increased power consumption and poor sensitivity, especially when in contact with the human body.

Innovation Solution

The RF front-end circuitry is adaptively tuned by sweeping the frequency spectrum to detect tunable notches or band stop elements, allowing for dynamic adjustment of filter and antenna combinations to optimize impedance matching and reduce power consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If traditional fixed filters and antennas are used to support multiple frequency bands, then the device can support various wireless technologies, but the RF front-end complexity increases and power consumption increases

Engineering Contradiction:

Improvesupport for multiple frequency bands and standardsVSAvoidRF front-end complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent applies dynamics by making the RF front-end tunable rather than fixed. The filter structure includes tunable elements that can dynamically adjust their frequency response to adapt to different operating conditions, frequency bands, and communication standards. This allows a single RF front-end design to efficiently support multiple frequency bands without requiring separate fixed filters for each band, thereby reducing overall complexity while maintaining versatility.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent utilizes parameter changes by allowing the filter characteristics (such as center frequency, bandwidth, and notch positions) to be dynamically adjusted through control signals. The tunable notches and band-stop elements can change their parameters in response to detected operating conditions, enabling the same hardware to optimize performance across different frequency bands and communication standards without physical reconfiguration.

Inventive Principle:

Principle #35Parameter changes

2Volume of moving object

If the antenna is placed in contact with the human body to enable compact form factor, then the device size is reduced, but impedance mismatch occurs and performance degrades

Engineering Contradiction:

Improvedevice sizeVSAvoidantenna performance

Core Design Contradiction:

Volume of moving objectVSReliability

Solution Approach 1:

The patent implements feedback mechanisms to monitor and detect changes in antenna impedance caused by proximity to the human body. The system uses detection signals to measure the actual impedance conditions and feeds this information back to the control unit, which then adjusts the tunable elements in the RF front-end to compensate for the impedance mismatch, maintaining optimal antenna performance despite the compact placement.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent applies dynamics by making the RF front-end tunable rather than fixed. The filter structure includes tunable elements that can dynamically adjust their frequency response to adapt to different operating conditions, frequency bands, and communication standards. This allows a single RF front-end design to efficiently support multiple frequency bands without requiring separate fixed filters for each band, thereby reducing overall complexity while maintaining versatility.

Inventive Principle:

Principle #15Dynamics

3Reliability

If reactive band stop filter structures are added to the RF front-end, then selectivity and spurious emission reduction improve, but the area required for the RF solution increases

Engineering Contradiction:

Improveselectivity and spurious emission reductionVSAvoidRF solution area

Core Design Contradiction:

ReliabilityVSArea of stationary object

Solution Approach 1:

The patent merges the band-stop filter functionality with existing RF front-end components rather than adding completely separate reactive filter structures. The tunable notches are integrated into the signal path using existing switches and capacitors that can be reconfigured to provide band-stop characteristics. This combining approach achieves the desired selectivity and spurious emission reduction while minimizing the additional area required compared to traditional separate filter implementations.

Inventive Principle:

Principle #5Merging (Combining)

Data Source

PatentUS9432112B2Mobile communication device and method for adaptive RF front-end tuning

Publication Date: 2016.08.30 INTEL CORP

AI summary

Examples of a system and method for adaptively tuning a radio frequency (RF) front-end are generally described herein. In some examples, the frequency of a transmit signal of RF front-end circuitry is swept in at least a part of the RF transmit band. RF power in a receiver is detected as a function of the RF frequency of the transmit signal to determine a location of at least one tunable notch or other band stop element in the frequency domain. Information from the detected RF power is determined as a function of the RF frequency of the transmit signal. The RF front-end circuitry is adjusted to a selected frequency response using the determined information.