Impedance Measurement System Using Segmented Amplifier Chains
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Solution Overview
Problem
Modern mobile communication devices with antennas, such as Planar Inverted F Antennas, face detuning issues due to environmental changes, necessitating an advanced impedance measurement system for adaptive impedance control to maintain optimal radiation characteristics.
Innovation Solution
An impedance measurement system comprising an input network with primary signal inputs, intermediate signal outputs, RSSI, limiter RSSI, and limiter chains, along with a subtraction circuit and phase detector, which derive impedance by calculating the ratio of signal strengths and phase differences, utilizing amplifier chains and a bipolar differential stage for accurate logarithmic and phase information processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an adaptive impedance control system is implemented to maintain optimal antenna radiation characteristics, then antenna performance is improved, but device complexity increases due to additional measurement and control circuits
Solution Approach 1:
The impedance measurement system is segmented into three separate amplifier chains (RSSI chain, limiter RSSI chain, and limiter chain), each dedicated to extracting specific information (signal strength, logarithmic signal strength, and phase). This segmentation allows parallel processing of different impedance parameters, improving measurement reliability while managing system complexity through functional decomposition
Solution Approach 2:
The amplifier chains are designed with multi-functionality, where each chain processes multiple signal aspects simultaneously. For example, the limiter RSSI chain provides both logarithmic signal strength information and phase information, reducing the need for separate dedicated circuits and thereby controlling overall system complexity
2Measurement precision
If multiple amplifier chains are used to extract both signal strength and phase information, then measurement precision is improved, but device complexity increases due to additional circuit components
Solution Approach 1:
The system employs dynamic signal processing where the amplifier chains operate in coordinated fashion to extract different impedance parameters. The limiter chains dynamically process signals to provide both amplitude and phase information, enabling precise impedance measurement while using a manageable number of circuit components through dynamic rather than static processing
Solution Approach 2:
The limiter RSSI chain acts as an intermediary that converts the intermediate signal into both logarithmic signal strength and phase information. This intermediary function allows a single chain to serve multiple measurement purposes, improving measurement precision without requiring separate dedicated chains for each parameter
Data Source
AI summary
An impedance measurement system (IMS) is provided that comprises an RSSI chain (RSSI), a limiter RSSI chain (LIMRSSI) and a limiter chain (LIM). The RSSI chain and the limiter RSSI chain are connected to a subtraction circuit (SC) and the limiter RSSI chain and the limiter chain are connected to a phase detector (PD). Further, a mobile communication device is provided that comprises the impedance measurement system in an adaptive impedance control system.