Dual-Antenna RF Demodulation Without a Local Oscillator
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Solution Overview
Problem
Existing RF signal reception architectures for millimeter bands are energy inefficient due to the need for local oscillators and are not applicable to all frequency ranges, particularly for short-range communications where energy consumption is a critical factor.
Innovation Solution
A device comprising a first and second antenna, a phase shifter, and a mixer that applies a phase shift to align signals from both antennas, allowing direct demodulation of amplitude-modulated RF signals without a local oscillator, enabling lower power consumption and directional reception.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a local oscillator is used in the reception architecture, then frequency synthesis and demodulation can be achieved, but power consumption increases significantly
Solution Approach 1:
The patent extracts and removes the local oscillator from the reception architecture, keeping only the essential components (antennas, amplifiers, phase shifters, and mixer). This eliminates the high power consumption source while maintaining the core functionality of signal reception and demodulation through direct multiplication of received signals.
Solution Approach 2:
The system uses the received RF signals themselves as the basis for demodulation, without requiring an external local oscillator. The mixer multiplies the signals from multiple antennas directly, allowing the received signals to serve their own demodulation purpose through phase comparison.
2Reliability
If a phased array antenna with programmable phase is used, then antenna gain and directional control are improved, but power consumption and architectural complexity increase
Solution Approach 1:
The patent segments the reception function into multiple independent antenna elements, each with its own amplifier and phase shifter. This allows directional control through phase comparison without requiring a complex programmable phased array architecture, reducing overall system complexity and power consumption.
Solution Approach 2:
The system uses multiple copies of simple antenna-amplifier-phase shifter units rather than a single complex programmable phased array. Each unit processes signals independently, and the mixer combines them to achieve directional reception, simplifying the overall architecture.
3Adaptability or versatility
If complex demodulation architectures are used, then demodulation capability is achieved, but the system becomes less applicable to millimeter-wave frequencies and more complex to produce
Solution Approach 1:
The patent uses simple, inexpensive components (basic antennas, amplifiers, phase shifters, and a mixer) that can be easily manufactured and integrated. These components are suitable for millimeter-wave frequencies and can be produced using standard PCB techniques, making the system adaptable and easy to manufacture.
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 solution reduces power consumption and allows for efficient demodulation of amplitude-modulated RF signals in millimeter bands, improving signal-to-noise ratio and enabling targeted reception, particularly suited for OOK and ASK modulation.
Implementation Method 1
a phase shifter (110) having an input electrically coupled to an output of the second amplifier (108) and configured to apply a phase shift φ to a signal received at its input
Implementation Method 2
a mixer (112) having a first input electrically coupled to an output of the phase shifter (110) and a second input electrically coupled to an output of the first amplifier (104), and configured to deliver on an output a product of signals applied to its first and second inputs
Data Source
Figure 1~2
Figure 3
AI summary
Device (100) for receiving and demodulating an amplitude-modulated RF signal, comprising: - a first antenna (102); - a first amplifier (104) coupled to the first antenna; - a receiving module (128) comprising: a) a second antenna (106); b) a second amplifier (108) coupled to the second antenna; c) a phase shifter (110) coupled to the second amplifier and applying a phase shift φ; d) a mixer (112) comprising inputs coupled to the phase shifter and the first amplifier, and delivering a product of signals received at the input, and in which the value of the phase shift φ is such that the device performs a demodulation of the RF signal when a wavefront (120) of the RF signal forms, with an alignment axis (116) of the antennas, an angle α having a particular value α which is a function of the phase shift φ and a distance between the antennas.