Parallel Resonant Transceiver for Magnetic Field Induction
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Solution Overview
Problem
Existing near field communication (NFC) systems using series resonant antennas are limited by the magnetic field strength they can achieve, as the current through the antenna cannot exceed the output of the power amplifier, compromising data transmission efficiency.
Innovation Solution
A transceiver with a parallel resonant circuit formed by an adjustable resistance and capacitance, allowing dynamic adjustment of the loaded quality factor to optimize data throughput by selecting appropriate modulation schemes based on signal-to-noise ratio (SNR) and channel conditions, thereby enhancing data transmission efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a series resonant antenna is used to power external passive tags, then the tag can be powered, but the magnetic field strength is limited and cannot exceed the current output by the power amplifier
Solution Approach 1:
The patent inverts the conventional series resonant configuration by using a parallel resonant circuit. This inversion allows the magnetic field strength to exceed the power amplifier output current limitation, as the parallel resonance creates a high impedance path that amplifies the magnetic field without requiring excessive current through the antenna itself.
Solution Approach 2:
The patent changes the resonant circuit configuration parameter from series to parallel. This parameter change fundamentally alters the relationship between current and magnetic field strength, enabling the magnetic field to be amplified beyond what is limited by the power amplifier output current in series configurations.
2Adaptability or versatility
If the resonant frequency is fixed, then the circuit is simple, but it cannot adapt to different signal bandwidths and data rates required by various modulation schemes
Solution Approach 1:
The patent introduces dynamic adjustability to the resonant circuit by making the capacitance variable. This allows the resonant frequency to be dynamically changed according to the requirements of different modulation schemes and data rates, enabling the system to adapt to varying communication conditions without requiring complete circuit redesign.
Solution Approach 2:
The patent creates a universal resonant circuit that can support multiple modulation schemes (QPSK, 16QAM, 64QAM, etc.) by combining the parallel resonant configuration with variable capacitance. This single circuit design provides multi-functionality across different data rates and modulation types, eliminating the need for separate fixed circuits for each mode.
3Adaptability or versatility
If a fixed resistance value is used in the parallel resonant circuit, then the circuit is simple, but the loaded quality factor cannot be adjusted to support different bandwidths and data rates
Solution Approach 1:
The patent makes the resistance value in the parallel resonant circuit dynamically adjustable. This allows the loaded quality factor to be optimized for different data rates and bandwidth requirements. The system can increase the quality factor for higher data rates that require narrower bandwidth, and decrease it for lower data rates that tolerate wider bandwidth.
Solution Approach 2:
The patent introduces variability to the resistance parameter in the parallel resonant circuit. This parameter change enables the system to adapt the loaded quality factor to match the requirements of different modulation schemes, optimizing performance across varying communication conditions without requiring separate circuits for each mode.
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 transceiver optimizes data throughput by dynamically adjusting the loaded quality factor of the parallel resonant circuit, supporting the required bandwidth and data rate for the selected modulation scheme, thereby achieving improved data transmission rates and magnetic field strength.
Implementation Method 1
a communications system that uses magnetic field induction to transmit data
Implementation Method 2
the antenna, capacitance and resistance form a parallel resonant circuit
Data Source
AI summary
The present application relates to a transceiver for use in a communications system that uses magnetic field induction to transmit data, the transceiver having an amplifier for driving an antenna, the amplifier forming, with a capacitance and a resistance connected in parallel with the antenna, a parallel resonant circuit. The resistance value of the resistance is adjustable, to permit adjustment of the loaded quality factor of the parallel resonant circuit. The transceiver includes a processing unit configured to determine the signal to noise ratio (SNR) of a signal received by the transceiver, and based on this SNR select a modulation scheme to apply to a data signal to be transmitted by the transceiver. The value of the resistance is adjusted to a level at which the loaded quality factor of the parallel resonant circuit is able to support the bandwidth and data rate required by the selected modulation scheme.