Cross-Coupled RF Amplifier Biasing for Millimeter Sensor Range
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Solution Overview
Problem
Millimeter-scale sensor devices face challenges in achieving long-range non-line of sight wireless communication due to limitations in antenna efficiency and power consumption, which restricts their communication range.
Innovation Solution
A wireless communication device is developed, incorporating a driver circuit with cross-coupled transistors and a bias circuit that adjusts bias currents for oscillation and signal amplification, allowing for efficient antenna operation in both transmit and receive modes, reducing power consumption and increasing communication range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If power amplifiers and low noise amplifiers are used to increase communication range, then communication range is improved, but power consumption increases
Solution Approach 1:
The bias circuit dynamically adjusts the bias current based on operating mode (transmit or receive) to optimize performance while minimizing power consumption. In transmit mode, a first bias current enables the driver circuit to oscillate the antenna effectively, while in receive mode, a second bias current amplifies received signals. This dynamic adaptation allows the system to achieve long communication range without continuously consuming high power.
Solution Approach 2:
The patent changes the bias current parameter between transmit and receive modes. The bias circuit switches between a first bias current for transmission and a second bias current for reception, where the second current is optimized to cancel resistive loss. This parameter change enables the same driver circuit to function efficiently in both modes, extending communication range while controlling power consumption.
2Length of moving object
If larger battery is used to support power amplifiers, then communication range is improved, but device size increases
Solution Approach 1:
The driver circuit serves multiple functions: it acts as an oscillator in transmit mode and as an amplifier in receive mode. The same circuitry with cross-coupled transistors performs both functions by switching bias currents, eliminating the need for separate power amplifiers and low noise amplifiers. This multi-functionality reduces the overall power requirement and allows millimeter-scale sensor devices to achieve long-range communication without requiring a larger battery or increased device size.
3Volume of moving object
If millimeter-scale sensor devices are used, then device size is reduced, but antenna efficiency and power consumption are limited
Solution Approach 1:
The bias circuit acts as an intermediary that optimizes the interaction between the driver circuit and the antenna. By providing mode-dependent bias currents, it enables the small antenna in the millimeter-scale device to operate efficiently. The bias circuit compensates for the limitations of small antennas by adjusting operating parameters, thereby maintaining reliable communication performance despite the reduced device size.
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 solution enhances the communication range of millimeter-scale sensor devices by optimizing antenna efficiency and power usage, enabling effective data exchange over longer distances with reduced power consumption.
Implementation Method 1
In a transmit mode, the bias circuit biases the driver circuit with a first bias current. In response to the first bias current, the driver circuit oscillates the antenna. In a receive mode, the bias circuit biases the driver circuit with a second bias current, such that the first bias current differs from the second bias current. In response to the second bias current, the bias circuit amplifies a signal received by the antenna.
Data Source
AI summary
A wireless communication device is presented for use with a sensor. The wireless communication device includes: an antenna, a driver circuit and a bias circuit. The driver circuit is electrically coupled to the antenna and includes at least one pair of cross-coupled transistors. The bias circuit is electrically coupled to the driver circuit. In a transmit mode, the bias circuit biases the driver circuit with a first bias current. In response to the first bias current, the driver circuit oscillates the antenna. In a receive mode, the bias circuit biases the driver circuit with a second bias current, such that the first bias current differs from the second bias current. In response to the second bias current, the bias circuit amplifies a signal received by the antenna.