Filter Circuit for RFID and GSM Harmonic Interference
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Solution Overview
Problem
In communication devices integrating multiple radio communication systems like RFID and GSM, the overlap of frequency bands leads to distortion and degradation of communication performance due to harmonic wave interference.
Innovation Solution
A communication device with a filter circuit that attenuates harmonic wave components, specifically designed to separate and manage signals between different frequency bands, ensuring that each system's performance is maintained without interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple radio communication systems (RFID and GSM) are integrated into a single communication device, then the device's functionality and versatility are improved, but harmonic wave interference and signal distortion occur between different frequency bands, degrading communication performance
Solution Approach 1:
The patent divides the frequency band handling into separate segments by introducing filter circuits for each radio communication system. The first filter circuit processes signals for the first frequency band (RFID) while the second filter circuit processes signals for the second frequency band (GSM), preventing interference between different systems and maintaining communication performance despite integration
Solution Approach 2:
The patent introduces filter circuits as intermediary components between the radio communication integrated circuits and the antenna elements. These filter circuits act as mediators that allow signals from different frequency bands to coexist without direct interference, enabling multiple systems to operate simultaneously with maintained performance
2Device complexity
If the frequency bands of different radio communication systems are placed in common, then the device complexity is reduced, but harmonic wave components generated by one system can be emitted as spurious responses from the other system's antenna elements
Solution Approach 1:
The patent extracts harmful harmonic wave components from the signal paths using filter circuits. The first filter circuit removes harmonic waves generated by the first radio communication integrated circuit, and the second filter circuit removes harmonic waves generated by the second radio communication integrated circuit, preventing these harmful signals from being emitted through the antenna elements
Solution Approach 2:
The patent converts the potentially harmful harmonic wave components into beneficial filtered signals. By using filter circuits with specific frequency responses, the harmonic waves that would normally cause interference are selectively attenuated or removed, transforming them from harmful factors into a controlled part of the signal processing mechanism
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The filter circuit effectively reduces harmonic wave emission, preventing interference between systems and maintaining the communication performance of both RFID and GSM systems when integrated.
Implementation Method 1
a filter circuit including a first frequency band as a pass band, and configured to attenuate the second communication signal or a harmonic wave component thereof
Implementation Method 2
a first radiator connected to the first radio communication integrated circuit and configured to radiate a first communication signal
Implementation Method 3
a second radiator connected to the second radio communication integrated circuit and configured to radiate a second communication signal
Data Source
AI summary
An RFID device provided at a transmission and reception circuit processes an RFID carrier signal belonging to a band of about 902 MHz to about 928 MHz or about 865 MHz to about 868 MHz to execute near field radio communication. An RFIC provided at a transmission and reception circuit processes a GSM carrier signal belonging to a band of about 824 MHz to about 894 MHz or about 880 MHz to about 960 MHz to execute mobile communication. A filter circuit provided at the transmission and reception circuit takes the band of about 850 MHz to about 940 MHz where RFID carrier signals appear as the pass band, and takes the band greater than or equal to about 1.2 GHz where a harmonic wave component of GSM carrier signals appears as the attenuation band.