Transceiver Front-End Isolation via Impedance Discontinuity
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Solution Overview
Problem
Current transceiver front-ends for communication devices face challenges in providing effective isolation between transmitters and receivers, particularly in frequency division duplex communication systems, where interference from the transmitter affects receiver performance, and existing solutions like duplexers are expensive, bulky, and require complex impedance tracking.
Innovation Solution
The implementation of a transceiver front-end with transmit and receive frequency blocking arrangements using a network of passive components, including transformers and filter arrangements, which block unwanted frequency signals while allowing desired signals to pass through, thereby isolating the transmitter and receiver without the need for complex impedance matching or dummy loads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If off-chip acoustic wave duplex filters are used to provide isolation between transmitter and receiver, then isolation performance is improved, but device size and cost increase
Solution Approach 1:
The patent combines the transmitter and receiver isolation functions into a single on-chip transceiver front-end device, integrating multiple functions (transmitter, receiver, and isolation mechanisms) that were previously implemented with separate off-chip duplex filters. This merging reduces the overall device size while maintaining isolation performance.
Solution Approach 2:
The patent introduces an artificial impedance discontinuity structure as an intermediary element between the transmitter and receiver pathways. This discontinuity acts as a mediator that reflects unwanted signals back to their source, providing isolation without requiring large off-chip duplex filters.
2Reliability
If off-chip acoustic wave duplex filters are used to provide isolation between transmitter and receiver, then isolation performance is improved, but cost increases
Solution Approach 1:
The patent replaces expensive off-chip acoustic wave duplex filters with a cost-effective on-chip implementation using standard semiconductor manufacturing processes. The artificial impedance discontinuity structure can be fabricated using conventional CMOS or similar processes, significantly reducing the cost of isolation functionality.
Solution Approach 2:
The patent substitutes the mechanical/acoustic wave filter system with an electrical impedance-based isolation mechanism implemented in integrated circuit form. This substitution eliminates the need for bulky acoustic wave devices and their associated packaging, reducing both cost and size.
3Reliability
If balance network with dummy load is used for signal cancellation, then isolation is achieved, but power loss increases and impedance tracking complexity increases
Solution Approach 1:
The patent extracts and eliminates the dummy load component from the isolation architecture. Instead of using a balance network with dummy load that dissipates power, the invention uses an artificial impedance discontinuity that reflects signals without requiring power-dissipating components, thereby reducing power loss while maintaining isolation.
4Reliability
If balance network with dummy load is used for signal cancellation, then isolation is achieved, but device complexity increases
Solution Approach 1:
The patent implements an artificial impedance discontinuity that automatically provides isolation based on inherent impedance mismatches in the transmission path. This self-service mechanism eliminates the need for complex active impedance tracking circuits and control systems, reducing device complexity while maintaining effective isolation.
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 provides efficient and area-effective isolation between transmitter and receiver, reducing power loss and eliminating the need for complex impedance tracking, while being easily tunable and suitable for integrated on-chip implementation, thus improving receiver performance and reducing costs.
Implementation Method 1
The transmit frequency blocking arrangement comprises a network of passive components comprising at least one transformer and a first filter arrangement adapted to have a higher impedance value at the transmit frequency than at the receive frequency
Implementation Method 2
The first filter arrangement is adapted to have a higher impedance value at the transmit frequency than at the receive frequency
Data Source
Figure 1~3b
Figure 4~5
Figure 6~7
AI summary
A transceiver front-end of a communication device is disclosed. The transceiver front-end is connectable to a signal transmission and reception arrangement adapted to transmit a transmit signal having a transmit frequency and to receive a receive signal having a receive frequency, to a transmitter adapted to produce the transmit signal, and to a receiver adapted to process the receive signal. The transceiver front-end comprises a transmit frequency blocking arrangement and a receive frequency blocking arrangement. The transmit frequency blocking arrangement has a blocking frequency interval associated with the transmit frequency and a non-blocking frequency interval associated with the receive frequency, and is adapted to block passage of transmit frequency signals between the signal transmission and reception arrangement and the receiver The receive frequency blocking arrangement has a blocking frequency interval associated with the receive frequency and a non-blocking frequency interval associated with the transmit frequency, and is adapted to block passage of receive frequency signals between the signal transmission and reception arrangement and the transmitter. The transmit frequency blocking arrangement comprises a network of passive components comprising at least one transformer and a first filter arrangement adapted to have a higher impedance value at the transmit frequency than at the receive frequency. The receive frequency blocking arrangement comprises a second filter arrangement adapted to have a higher impedance value at the transmit frequency than at the receive frequency and a third filter arrangement adapted to have a higher impedance value at the receive frequency than at the transmit frequency.