Shunt Switch Impedance Control for Wireless Transceiver Isolation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional wireless transceivers face inefficiencies due to series switches used for isolation between transmit and receive circuits, which introduce parasitic components, leading to signal loss and increased costs from off-chip devices.
Innovation Solution
Incorporating shunt switches on an integrated circuit to vary impedance by inserting or removing components in parallel with matching networks, minimizing signal losses and reducing the need for off-chip devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If series switches are used to isolate transmit and receive circuits, then isolation between circuits is improved, but signal loss increases due to parasitic components
Solution Approach 1:
The patent inverts the conventional series switch configuration by using shunt (parallel) switches connected to ground. Instead of placing switches in the signal path to block signals, the invention places switches in parallel paths to ground, where they can selectively connect or disconnect the transmit and receive circuits from the antenna without introducing series parasitics into the main signal path.
Solution Approach 2:
The patent introduces shunt switches as intermediary elements that mediate between the transmit/receive circuits and the antenna. These switches act as controlled connections to ground, providing isolation when closed and allowing signal passage when open, thereby eliminating the need for series switches that directly interrupt the signal path.
2Reliability
If series switches are used for circuit isolation, then transmit-receive isolation is improved, but device complexity increases due to off-chip components
Solution Approach 1:
The patent merges the isolation function with the existing transmit and receive circuit paths by integrating shunt switches directly into the circuit architecture. Instead of adding separate series switches in the signal path, the invention combines the isolation capability with the existing circuit topology by placing switches in parallel to ground, thereby reducing the total number of components.
Solution Approach 2:
The shunt switches serve multiple functions: they provide circuit isolation when closed, allow signal passage when open, and can be integrated into the same chip as the transmit and receive circuits. This multi-functionality eliminates the need for separate off-chip isolation components, reducing overall device complexity.
3Reliability
If series switches are placed in signal paths, then isolation is achieved, but manufacturing cost increases due to off-chip devices
Solution Approach 1:
The patent combines the isolation function with the existing transmit and receive circuit fabrication processes by integrating shunt switches into the same semiconductor chip. This merging of functions into a single integrated structure eliminates the need for separate off-chip isolation devices, thereby reducing manufacturing costs associated with multiple discrete components.
Data Source
AI summary
Circuits, methods, and apparatus that provide isolation between receive and transmit circuits in a wireless transceiver. One example provides switches that can be included on an integrated circuit with at least portions of a wireless transceiver. These switches vary the impedance of transmitter and receiver circuits between a termination impedance and a high impedance by inserting or removing components in parallel with matching networks. Signal losses are minimized since these switches are shunt connected to input and output paths on the wireless circuit and are not connected directly in either signal path.