RF Transmitter Antenna Equalization for Narrowband Efficiency

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Solution Overview

Problem

Existing wireless communication systems with electrically small antennas face challenges in maintaining efficient signal transmission and reception due to the trade-off between antenna bandwidth and signal distortion, leading to reduced link budget and data rate when the antenna bandwidth is too narrow.

Innovation Solution

A wireless communication system is designed with narrowband antennas where the antenna bandwidth is marginally larger than the signal bandwidth, with equalization filters to compensate for amplitude and phase distortion, allowing for efficient transmission and reception even at lower bandwidth ratios, and frequency transposition units to adapt the frequency range.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If the antenna bandwidth is reduced to improve antenna efficiency, then antenna efficiency is improved, but signal distortion increases

Engineering Contradiction:

Improveantenna efficiencyVSAvoidsignal distortion

Core Design Contradiction:

Loss of energyVSLoss of information

Solution Approach 1:

The system separates the antenna function from the signal processing function. The antenna operates at its optimal narrow bandwidth for efficiency, while a dedicated distortion compensation unit processes the signal to remove amplitude and phase distortion caused by the narrow bandwidth, effectively dividing the overall function into specialized components

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

A distortion compensation unit is introduced as an intermediary component between the narrowband antenna and the signal processing chain. This intermediary unit specifically addresses the signal distortion problem caused by the narrowband antenna without affecting the antenna's efficiency benefits

Inventive Principle:

Principle #24Intermediary (Mediator)

2Power

If the antenna bandwidth is made narrow to improve link budget, then link budget is improved, but data rate is reduced

Engineering Contradiction:

Improvelink budgetVSAvoiddata rate

Core Design Contradiction:

PowerVSProductivity

Solution Approach 1:

The system changes the bandwidth parameter of the antenna to be narrow (BWant ≤ BWsig) to improve link budget, while simultaneously using distortion compensation to maintain signal quality, thereby achieving better power efficiency without completely sacrificing data rate capability

Inventive Principle:

Principle #35Parameter changes

3Loss of information

If the antenna bandwidth is widened to reduce signal distortion, then signal distortion is reduced, but antenna efficiency decreases

Engineering Contradiction:

Improvesignal distortionVSAvoidantenna efficiency

Core Design Contradiction:

Loss of informationVSLoss of energy

Solution Approach 1:

The distortion compensation function is extracted from the antenna design itself and placed in a separate compensation unit. This allows the antenna to be optimized purely for efficiency with narrow bandwidth, while the extracted compensation unit handles the signal distortion correction separately

Inventive Principle:

Principle #2Taking out (Extraction)

4Loss of energy

If traditional narrowband antennas are used, then antenna efficiency is improved, but the antenna bandwidth becomes insufficient for modern wideband signals

Engineering Contradiction:

Improveantenna efficiencyVSAvoidbandwidth compatibility

Core Design Contradiction:

Loss of energyVSAdaptability or versatility

Solution Approach 1:

The system dynamically compensates for the static narrowband antenna characteristics through real-time distortion compensation. The compensation unit adapts to the signal requirements and actively corrects the frequency response, making the narrowband antenna effectively adaptable to various signal bandwidths despite its fixed physical characteristics

Inventive Principle:

Principle #15Dynamics

Data Source

PatentEP3012982B1Radio frequency transmitter and receiver parts with a modulation bandwidth comparable to or exceeding the bandwidth of the transmitter and/or receiver antennas

Publication Date: 2020.05.27 OTICON

Figure 1a~1c
Figure 2a~2c
Figure 3~4

AI summary

The application relates to a radio frequency transmitter part for transmitting radio signals within a first frequency band of width BWsig via an antenna and a tuning circuit, the antenna and the tuning circuit together being tuned to a second frequency band of width BWant overlapping with the first frequency band and fulfilling the relation BWant = k.BWsig, and the antenna bandwidth BWant is defined as the -3dB bandwidth of the loaded antenna, and the signal bandwidth BWsig is defined as the bandwidth within which 99% of the signal power is located, wherein k is smaller than 0.75, the transmitted signals are modulated according to a digital modulation scheme, and the transmitter part is adapted to pre-compensate within the entire first frequency band for such phase and/or amplitude changes to the transmitted radio signals that are caused by the antenna and the tuning circuit. The application further relates to a corresponding radio frequency receiver part. This has the advantage of providing a wireless communication system suitable for use in relatively small and/or low power devices. The invention may e.g. be used for the handheld communication devices, e.g. listening devices, e.g. hearing aids, involving wireless communication.