Coupled Antenna Detuning Using Computed Load Impedance
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Solution Overview
Problem
The mutual coupling between transmit and receive antennas in user equipment (UE) leads to a loss in total radiated power (TRP) due to dissipation of transmit power in low-noise amplifiers, which is exacerbated by varying orientations and handling of the UE, affecting antenna impedance and signal-to-noise ratio.
Innovation Solution
A UE equipped with an antenna switch module and a directional coupler performs computation-based detuning by determining scattering parameters between antennas, using adjustable or fixed loads to minimize coupling, thereby optimizing antenna impedance and enhancing TRP.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If multiple antennas are used to increase data rate through MIMO and beamforming, then signal strength and achievable data rate are improved, but antenna coupling increases causing loss in total radiated power
Solution Approach 1:
The patent implements dynamic detuning by adjusting the impedance of receive antennas in real-time based on detected coupling conditions. The system continuously monitors the coupling between transmit and receive antennas and dynamically modifies the receive antenna impedance to minimize coupling effects, thereby maximizing total radiated power during transmission.
Solution Approach 2:
The system changes the impedance parameter of receive antennas to optimize performance. By adjusting the complex impedance value of receive antennas based on detected coupling conditions, the system minimizes power dissipation in low-noise amplifiers while maintaining effective signal reception.
2Power
If antenna coupling is reduced by increasing distance or changing orientation, then power loss is minimized, but device compactness and flexibility are compromised
Solution Approach 1:
The patent introduces an intermediary impedance adjustment mechanism between the transmit and receive antennas. This intermediary system modifies the electrical characteristics of receive antennas to decouple them from transmit antennas, allowing compact physical arrangements while maintaining power efficiency through electrical isolation rather than physical separation.
3Measurement precision
If antenna coupling is measured through time-consuming test measurements, then accurate coupling characterization is achieved, but measurement time and complexity increase
Solution Approach 1:
The system performs self-characterization by using its own transmit signals to measure coupling conditions. The UE transmits test signals through its own antennas and measures the resulting coupling effects on receive antennas, eliminating the need for external measurement equipment and time-consuming laboratory tests. This self-service approach provides accurate coupling characterization in real-time.
Solution Approach 2:
The system performs preliminary coupling measurements and characterizations before actual data transmission begins. By pre-characterizing the coupling conditions using built-in test signals and measurements, the system prepares optimal detuning parameters in advance, avoiding time-consuming measurements during operation and enabling rapid adaptation to changing coupling conditions.
Data Source
AI summary
A user equipment (UE) is provided that detunes a receive antenna while a transmit antenna transmits. To determine the detuning, the UE first transmits a signal through the transmit antenna while the receive antenna is sequentially coupled through known loads. At each load, the UE determines an input reflection coefficient for a transmit path to the transmit antenna. Based upon the known loads and the corresponding input reflection coefficients, the UE determines a load to couple to the receive antenna to perform the detuning.