Coexistence Radio Front-End Circuitry Using Phase-Shifted Isolation Nulls
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Solution Overview
Problem
Devices with coexistence radios face interference and operational disruptions when sharing the same frequency band, leading to issues like data loss, reduced signal quality, and decreased bandwidth due to the coexistence of multiple wireless technologies.
Innovation Solution
The implementation of RF front-end circuitry with a directional coupler and phase-shifter circuit allows two radios to share an antenna and frequency band by creating an isolation null at an isolated port, canceling out interference and enabling concurrent operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If two radios share the same antenna and frequency band, then device complexity is reduced, but interference between transmit and receive signals occurs
Solution Approach 1:
The patent segments the signal paths by using a directional coupler to separate transmit and receive signals into different ports. The coupler divides the antenna connection into multiple isolated paths, allowing simultaneous transmit and receive operations without mutual interference.
Solution Approach 2:
The directional coupler acts as an intermediary device between the antenna and the radios. It mediates the signal flow by directing transmit signals to the transmit radio and receive signals to the receive radio, preventing direct interference between the two signal paths.
2Reliability
If a directional coupler is used to isolate signals, then signal quality is improved, but device complexity increases
Solution Approach 1:
The directional coupler performs multiple functions simultaneously: it isolates transmit and receive signals, provides impedance matching, and enables full-duplex operation. This multi-functionality reduces the need for additional separate components, thereby limiting the increase in overall device complexity.
3Object-affected harmful factors
If phase-shifter circuit is added to create isolation null, then interference cancellation is improved, but device complexity increases
Solution Approach 1:
The phase-shifter circuit changes the phase parameter of the transmit signal to create a 180-degree phase difference (isolation null) at the receive port of the directional coupler. This parameter change enables destructive interference of the transmit signal at the receive path, effectively canceling interference without requiring additional isolation components.
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 isolates receive signals from transmit signals, reducing interference and maintaining signal quality, even with high antenna mismatch, thereby enhancing the operational robustness and efficiency of devices with coexistence radios.
Implementation Method 1
causing a phase-shifter circuit to change a phase of the reflected wave to a second phase that is 90-degrees from the first phase
Implementation Method 2
An isolation null that cancels a copy of the incident wave that is present at the third port as a result of the incident wave being applied to the first port
Data Source
AI summary
Technologies directed to sharing an antenna and a frequency band between coexistence radios are described herein. In one device, semi-active front-end circuitry includes a directional coupler and a phase-shifter circuit coupled to two radios that use the same antenna and the same frequency band. The phase-shifter circuit and directional coupler create an isolation null at an isolated port of the directional coupler that cancels a copy of an incident wave of a transmit signal being applied at an input port of the directional coupler. The isolation null permits the second radio to receive a receive signal concurrently with the first radio transmitting the transmit signal.