Single Antenna Full Duplex via Variable Impedance
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Solution Overview
Problem
Current communication systems face challenges in achieving effective full-duplex operation with a single antenna due to hardware limitations, such as signal leakage and space constraints, which are not adequately addressed by existing solutions like circulators that are bulky and unsuitable for miniaturization.
Innovation Solution
A system utilizing a signal coupler with a variable impedance element comprising a variable phase shifter and attenuator, connected to a single antenna, allows for independent tuning of the reflection coefficient to isolate transmit and receive signals, enabling efficient full-duplex operation by adjusting the magnitude and phase of the reflection coefficient.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a single antenna is used for full-duplex operation, then space is saved and device size is reduced, but signal leakage from transmit to receive path increases causing interference
Solution Approach 1:
A variable impedance element is introduced as an intermediary component between the transmit and receive paths. This element dynamically adjusts the impedance to cancel out the harmful transmit signal leakage in the receive path, enabling effective isolation without requiring physical separation of antennas or bulky circulators.
Solution Approach 2:
The system dynamically changes the impedance parameter of the variable impedance element to adapt to different operating conditions. By adjusting the impedance magnitude and phase, the system optimally cancels signal leakage across varying frequencies and power levels, maintaining effective isolation while using a single antenna.
2Object-generated harmful factors
If circulators are used to isolate transmit and receive paths, then signal leakage is reduced, but device size increases and miniaturization becomes difficult
Solution Approach 1:
The invention extracts and eliminates the need for bulky circulator components by using a different isolation mechanism. The variable impedance element provides the necessary transmit-receive isolation through impedance transformation and signal cancellation, removing the requirement for large magnetic components while achieving the same harmful factor reduction.
Solution Approach 2:
The patent replaces the mechanical/magnetic circulator system with an electrical impedance-based isolation mechanism. Instead of using physical magnetic fields and directional coupling structures, the system uses electronic impedance adjustment to achieve signal path isolation, enabling miniaturization.
3Object-generated harmful factors
If spatial separation of transmit and receive antennas is used, then signal leakage is minimized, but space requirements increase making it unsuitable for compact devices
Solution Approach 1:
The invention merges the transmit and receive antenna functions into a single antenna structure. By combining both functions in one element and using a variable impedance element to manage the interaction between transmit and receive paths, the system achieves effective isolation without requiring multiple physically separated antennas.
4Productivity
If full-duplex operation is implemented with a single antenna, then data rates are increased, but interference management becomes more complex
Solution Approach 1:
The system employs a dynamic variable impedance element that continuously adapts its impedance characteristics based on operating conditions. This dynamic adjustment simplifies interference management compared to static isolation methods, as the impedance automatically optimizes to cancel leakage across varying frequencies, power levels, and environmental conditions, enabling robust full-duplex operation.
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 effectively reduces interference between transmitted and received signals, improving isolation and enabling full-duplex operation on the same frequency, even in space-constrained devices, with improved signal-to-noise ratio and reduced signal loss.
Implementation Method 1
independent tuning of the magnitude and phase of the reflection coefficient
Implementation Method 2
variable impedance element to reduce interference between the signals for transmission by the antenna and the signals received by the antenna
Data Source
AI summary
A system and method for duplexing radio frequency signals for full-duplex transmission and reception by an antenna. The system comprises a signal coupler comprising an antenna node configured to be connected to the antenna, an input node for receiving radio frequency signals for transmission by the antenna, an output node for outputting radio frequency signals received by the antenna, and a coupling node. The system further comprises a variable impedance element connected to the coupling node to reduce interference between the signals for transmission by the antenna and the signals received by the antenna, the variable impedance element comprising a variable phase shifter connected to a variable attenuator.