Antenna Switch Phase Shifter for Carrier Aggregation Isolation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In antenna apparatuses supporting carrier aggregation, signal interference and fade occur due to signal flow through a common terminal in switch simultaneous connection states, leading to deteriorated isolation between RF modules.
Innovation Solution
The antenna apparatus includes a switch with a common terminal connected to an antenna element, a first signal path with an RF circuit providing open or shorted impedance in the second frequency band, and a phase shifter with a coil and capacitor configuration that ensures high impedance in the second frequency band, reducing signal interference by preventing signal flow through the common terminal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If RF modules are connected by a switch for carrier aggregation, then multi-band signal processing capability is improved, but signal interference and fade occur due to signal flow through the common terminal
Solution Approach 1:
The patent introduces a phase shifter as an intermediary component in the signal path between the switch common terminal and the RF module. This phase shifter modifies the phase of signals passing through, creating a phase difference that prevents direct signal flow and interference through the common terminal, thereby resolving the contradiction between maintaining switch connectivity and preventing signal interference.
Solution Approach 2:
The patent changes the electrical parameters (phase and impedance characteristics) of the signal path by incorporating the phase shifter. By adjusting the phase parameter of signals in different frequency bands, the system prevents constructive interference and signal fade that would otherwise occur through the common terminal, while maintaining the ability to process multiple frequency bands.
2Ease of operation
If the impedance of RF module is not open but shorted, then connection to common terminal is improved, but isolation between RF modules deteriorates
Solution Approach 1:
The phase shifter serves as a mediator between the common terminal and the RF module, introducing a phase shift that effectively isolates the RF modules from each other while maintaining their connection to the common terminal. This intermediary component prevents direct signal coupling between modules that would occur with simple shorted impedance connections.
Solution Approach 2:
The phase shifter applies a preliminary phase shift to signals before they can cause interference between RF modules. By pre-modifying the signal phase, the system prevents the harmful interaction between modules that would otherwise occur when they are both connected to the common terminal with shorted impedance.
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 configuration significantly reduces or prevents signal interference and fade by maintaining high impedance in the second frequency band, minimizing the impact of the RF circuit on signal paths and ensuring effective carrier aggregation.
Implementation Method 1
a second coil that magnetic-field couples to the first coil with a coupling coefficient of less than 1
Implementation Method 2
a capacitor provided between the first port and the second port
Data Source
AI summary
An antenna apparatus includes an antenna element, a switch with a common terminal that is electrically connected to the antenna element side, a first signal path provided between a first input/output terminal of the switch and a first communication circuit, and a second signal path provided between a second input/output terminal of the switch and a second communication circuit. The first signal path includes a radio-frequency circuit and a phase shifter, and the RF circuit has an impedance that is open or shorted in a second frequency band as seen from the antenna element side. In a state in which the first input/output terminal and the second input/output terminal are both electrically connected to the common terminal, the phase shifter provides a phase shift, and the impedance in the second frequency band of the first signal path as seen from the common terminal is open.