Adjustable Impedance Directional Couplers for RF Load Determination
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Solution Overview
Problem
Modern mobile communication devices face issues with impedance mismatch between RF generation circuitry and antennas, leading to excess power consumption and weak signals, resulting in reduced talk time and increased battery drain.
Innovation Solution
A communication device with directional couplers and adjustable impedances, a return loss measurement circuit, and a load impedance determination circuit to optimize impedance matching by setting adjustable impedances and determining return losses, allowing for precise load impedance calculation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If impedance matching is not optimized, then device complexity remains low, but power consumption increases and signal strength decreases
Solution Approach 1:
The patent introduces directional couplers as intermediary components in the signal path between the RF generation circuitry and the antenna. These couplers enable precise measurement of forward and reflected signals, allowing the system to determine load impedance and optimize impedance matching without adding excessive complexity to the overall device architecture.
Solution Approach 2:
The patent implements a feedback mechanism where the return loss measurement circuit continuously monitors the impedance matching condition by measuring the reflected signal. The load impedance determination circuit processes these measurements and provides feedback to adjust the impedance matching network, ensuring optimal power transfer while maintaining manageable device complexity through automated control.
2Duration of action of moving object
If impedance matching is not optimized, then talk time is reduced, but manufacturing precision requirements remain low
Solution Approach 1:
The patent employs dynamically adjustable impedance matching networks that can adapt to changing operating conditions, antenna characteristics, and environmental factors. The adjustable impedances in the directional couplers and impedance matching network allow the system to optimize power transfer in real-time, extending talk time without requiring extremely precise fixed manufacturing tolerances.
3Measurement precision
If return loss measurement is performed for multiple impedances, then load impedance determination precision improves, but measurement time increases
Solution Approach 1:
The patent performs return loss measurements for multiple different impedances in advance to build a comprehensive data set for load impedance determination. By pre-characterizing the system response across multiple impedance values, the patent creates a reference framework that enables accurate load impedance calculation without requiring extensive real-time measurements, thus reducing measurement time while maintaining high precision.
Data Source
AI summary
According to one embodiment, a communication device is described comprising an antenna, a signal path for supplying a signal to the antenna, two directional couplers arranged within the signal path, wherein each directional coupler is coupled to an adjustable impedance defining the characteristic impedance of the directional coupler, a controller configured to set, for each of a plurality of impedances, the adjustable impedances of the directional couplers to the impedance, a return loss measurement circuit configured to determine, for each of the plurality of impedances, a return loss of the signal path when the adjustable impedances of the directional couplers are set to the impedance and a load impedance determination circuit configured to determine a load impedance of the signal path based on the determined return losses.