Multi-Antenna Directional Backscatter Tags for Extended Range
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Solution Overview
Problem
The range of backscatter tags, such as RFID tags, is limited due to their lack of a power source or limited power, restricting their application in various fields.
Innovation Solution
The implementation of multi-antenna, directional backscatter tags using a 3×3 antenna array with phase conjugation techniques and load modulation to enhance directivity and range, enabling up to 19 dB sensitivity improvement and tripled range compared to single antenna tags.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a single antenna is used in backscatter tags, then the device complexity is low, but the range and sensitivity are limited
Solution Approach 1:
The patent divides the antenna system into multiple segmented elements (e.g., 3×3 array with 9 antennas) that can be independently controlled. Each antenna element can be individually switched and phase-modulated, allowing the system to achieve superior range and sensitivity through coherent combining while maintaining manageable complexity through modular architecture.
Solution Approach 2:
The patent transitions from a single-point antenna to a two-dimensional array configuration. This spatial dimensionality enables beamforming and directional control, where antennas are arranged in a grid pattern that provides angular selectivity and constructive interference in specific directions, thereby extending effective range beyond what a single antenna can achieve.
2Reliability
If multiple antennas are used to enhance range, then the sensitivity and range improve, but the device complexity increases
Solution Approach 1:
The patent combines multiple antenna elements with their associated switching and phase control circuits into an integrated array system. The individual antenna outputs are coherently combined through phase conjugation techniques, where signals from multiple antennas are synchronized in phase and amplitude to constructively interfere, achieving sensitivity enhancement equivalent to signal integration while managing the complexity through unified control architecture.
Solution Approach 2:
The patent employs dynamic switching and phase modulation of individual antenna elements based on incoming signal direction. The system adaptively adjusts the phase and amplitude of each antenna element in real-time to maintain optimal beamforming performance, allowing the array to track and respond to signals from different angles while maintaining high sensitivity.
3Ease of operation
If directional beamforming is implemented, then the directivity improves, but the control complexity increases
Solution Approach 1:
The patent implements feedback mechanisms where the system monitors incoming signal characteristics (arrival angle, strength) and adjusts the phase and amplitude of each antenna element accordingly. This closed-loop control enables automatic beam steering and directional focusing without manual intervention, achieving high directivity while the control complexity is managed through automated adaptation to signal conditions.
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 multi-antenna approach significantly enhances the range and directivity of backscatter signals, allowing for improved data transfer and security by achieving up to 19 dB sensitivity enhancement and tripled range, while also enabling quadrature phase shift keying modulation for data transmission.
Implementation Method 1
Backscatter tags (e.g., RFID tags) are widely used for a variety of applications
Implementation Method 2
a first throw terminal connected to a first side of an inductor for that switch
Implementation Method 3
a second throw terminal connected to a first side of a capacitor for that switch
Data Source
AI summary
Backscatter tags, comprising: antennas; single pole, multiple throw switches each switch (S) having pole terminal connected to one of the antennas, and each having first throw terminal (TT) connected to first side (FS) of inductor (I) for S, second TT connected to FS of capacitor (C) for S, third TT connected to fixed voltage level (FVL), fourth TT that is floating, wherein second side (SS) of I and SS of C are connected to the FVL; power combiner (PC) having inputs connected to fifth TT of each of two of the switches; power detector (PD) having an input connected to output of PC; analog to digital converter (ADC) having input connected to output of PD; hardware processor coupled to output of the ADC and coupled to control terminal of each of the switches.