Impedance-Switched Transmission Circuit for Single-Sideband Backscatter
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Solution Overview
Problem
Existing backscatter systems in wireless communication devices face challenges in efficiently suppressing either the upper sideband (USB) or lower sideband (LSB) signal, which limits their ability to achieve single sideband (SSB) communication effectively.
Innovation Solution
The proposed solution involves a transmission circuit configured with multiple impedance circuits, switch elements, a compensation circuit, and a control circuit. This configuration allows for the selective addition of capacitance and resistance values, enabling the control circuit to rotate the reflection coefficient of the output terminal on the antenna side in the complex plane, thereby selectively suppressing either the USB or LSB signal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a demultiplexer/multiplexer is used to suppress either USB or LSB signal, then single sideband communication is achieved, but device complexity increases
Solution Approach 1:
The patent changes the impedance parameters of the transmission circuit by selectively connecting different impedance circuits with specific resistance and capacitance values. This allows rotation of the reflection coefficient in the complex plane to suppress either USB or LSB signals, achieving SSB communication without requiring complex demultiplexer/multiplexer structures
Solution Approach 2:
The transmission circuit is divided into multiple impedance circuits (first, second, third impedance circuits) with different impedance characteristics. Each impedance circuit contains specific resistance and capacitance elements that can be selectively connected through switch elements, allowing flexible impedance adjustment to achieve signal suppression
2Adaptability or versatility
If multiple impedance circuits with different characteristics are used to rotate reflection coefficient, then signal suppression capability is improved, but device complexity increases
Solution Approach 1:
The multiple impedance circuits serve multiple functions: they can be selectively connected to achieve different impedance values, rotate the reflection coefficient to different positions in the complex plane, and suppress different sidebands (USB or LSB) as needed. This multi-functionality reduces the need for separate dedicated circuits for each function
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
This approach effectively achieves single sideband communication by rotating the reflection coefficient, allowing for the suppression of either the USB or LSB signal, thus enhancing the communication efficiency in backscatter systems.
Implementation Method 1
a compensation circuit connected to each of the plurality of switch elements and selectively adding a capacitance value and a resistance value to the transmission circuit
Data Source
AI summary
A transmission circuit includes a plurality of impedance circuits, each of which has a different impedance, a plurality of switch elements, any one of which is being connected to a respective one of the plurality of impedance circuits, a compensation circuit connected to a respective one of the plurality of switch elements and selectively adding a capacitance value and a resistance value to the transmission circuit. and a control circuit controlling opening/closing of the plurality of switch elements. The control circuit is controllable to selectively change the opening/closing of the plurality of switch elements and to rotate a reflection coefficient of an output terminal on an antenna side in a complex plane.