Switchable Impedance Matching Circuit for Single Antenna Systems
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Solution Overview
Problem
The size constraint of electronic devices limits the number of antennas they can include, often necessitating the use of a single antenna for multiple signal frequencies, which can lead to impedance mismatch issues and substantial signal power loss.
Innovation Solution
A mobile communication device is equipped with a switchable impedance matching circuit coupled between an antenna and both a WLAN transceiver and a GPS receiver. A controller determines the device's state (indoor or outdoor) and sets the impedance matching circuitry accordingly, allowing the antenna to communicate either WLAN or GPS signals effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a single antenna is used for multiple signal frequencies, then the device size is reduced, but impedance matching performance deteriorates
Solution Approach 1:
The patent implements a switchable impedance matching circuit that dynamically adjusts impedance parameters based on the operating frequency band. The circuit includes multiple impedance elements (inductors and capacitors) that can be selectively connected or disconnected through switches, allowing the antenna system to adapt its impedance characteristics when transitioning between WLAN and GPS frequency bands, thereby maintaining optimal impedance matching performance across different bands while using a single antenna
Solution Approach 2:
The patent changes the electrical parameters of the impedance matching circuit by switching between different combinations of inductors and capacitors. The controller detects the current operating band and adjusts the impedance matching network parameters accordingly, transforming the circuit from a static configuration to a dynamically adjustable one that optimizes performance for each specific frequency band
2Device complexity
If a single antenna is used for multiple signal frequencies, then the device complexity is reduced, but signal power loss increases
Solution Approach 1:
The switchable impedance matching circuit dynamically reconfigures the electrical connection topology between the antenna and receiving/transmitting circuits based on the operating band. This dynamic adjustment ensures maximum power transfer efficiency by maintaining proper impedance matching, thereby reducing signal power loss that would otherwise occur with a fixed-configuration circuit
Solution Approach 2:
The impedance matching circuit acts as an intermediary component between the single antenna and the different receiving/transmitting circuits. This intermediate circuit transforms the antenna's output impedance to match the input impedance of the WLAN or GPS receiver, preventing signal power loss that would result from direct connection without impedance transformation
Data Source
AI summary
A system for controlling an impedance matching circuitry can include an antenna, a receiving or transmitting circuitry, an impedance matching circuitry, a circuitry, and a controller. The impedance matching circuitry can be coupled between the antenna and the receiving or transmitting circuitry. The circuitry can be configured to set a value of an impedance of the impedance matching circuitry. The controller can be configured to determine, based on a state of an electronic device, that the electronic device is configured to perform one or more functions with one or more of a satellite radio navigation signal at a first or a second frequency, a wireless local area network signal at a third or a fourth frequency, or a personal area network signal at a fifth or a sixth frequency. The controller can be configured to control, in response to a determination of the state of the electronic device, the circuitry.