Balanced Duplexer Isolation Circuit for Single-Cable Full Duplex
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Solution Overview
Problem
Existing wireless communication devices using frequency division duplex (FDD) transceivers face limitations in bandwidth for transmitting and receiving signals, and require multiple cables, which increases device size and reduces space for additional circuitry.
Innovation Solution
A full-duplex transceiver with two circuit paths between antennas and an isolation circuit, utilizing a non-reciprocal phase shifter and balun to enable simultaneous transmission and reception of signals over the same frequency range, reducing the need for multiple cables.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If frequency division duplex (FDD) transceiver is used to isolate transmitter and receiver, then interference is reduced, but bandwidth is limited to about 100 MHz for each operation
Solution Approach 1:
The patent changes the fundamental operating parameters from frequency division (FDD) to time-division or code-division multiplexing, allowing both transmit and receive signals to occupy the same frequency band while being separated in time or code domains. This parameter change enables bandwidth expansion from 100 MHz to potentially the full available spectrum while maintaining isolation through sophisticated signal processing.
Solution Approach 2:
The patent makes the single cable universal by enabling it to carry both transmit and receive signals simultaneously over the same frequency range. The cable becomes multi-functional, handling bidirectional communication without requiring separate dedicated cables for transmit and receive operations, thus expanding bandwidth while reducing cable requirements.
2Reliability
If two cables are used for transmitting and receiving signals at different frequency ranges, then signal isolation is maintained, but device size increases and space for additional circuitry is reduced
Solution Approach 1:
The patent merges the functions of two separate cables (transmit and receive) into a single cable that handles both bidirectional communication. By combining these functions and using advanced signal processing to maintain isolation, the device volume is reduced while preserving signal isolation through intelligent separation of transmit and receive signals in the same physical medium.
Solution Approach 2:
The single cable becomes universal, performing both transmit and receive functions simultaneously over the same frequency range. This multi-functionality eliminates the need for separate dedicated cables, reducing device size while maintaining isolation through time-division or code-division multiplexing techniques.
3Reliability
If two cables are used for transmitting and receiving signals, then communication reliability is improved, but space for additional circuitry is reduced
Solution Approach 1:
The patent combines multiple cable functions into a single cable system, freeing up device space that can then be utilized for additional circuitry. The merging of transmit and receive functions into one cable creates physical space for enhanced processing circuits, improving both communication reliability through better signal handling and adaptability through additional functionality.
Solution Approach 2:
By changing from frequency-division to time-division or code-division multiplexing, the patent enables more efficient use of the single cable's capacity, improving communication reliability through sophisticated signal separation. The freed-up space allows for additional circuitry that can further enhance reliability and add versatile functions to the device.
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
The full-duplex transceiver increases bandwidth availability for both transmitting and receiving signals, potentially up to 100 MHz to 1000 MHz, and allows for a single cable to be used, reducing device size and enabling more circuitry to be incorporated.
Implementation Method 1
A non-reciprocal phase shifter may be used to shift a phase of a signal propagating along one of the circuit paths and further improve isolation of the transmitter circuit from received signals and the receiver circuit from transmission signals
Implementation Method 2
A first balun coupling the first signal path to the second signal path
Data Source
AI summary
Embodiments disclosed herein relate to improving an available bandwidth for a transceiver of an electronic device and to reducing a footprint of an associated integrated circuit of the electronic device. To do so, an isolation circuit is disposed between a transmit circuit and a receive circuit. The isolation circuit has first and second signal paths. A first portion of the signal propagates along the first signal path and a second portion of the signal propagates along the second signal path. A non-reciprocal phase shifter is disposed on the first signal path to shift a phase of the first portion to match a phase of the second portion and improve isolation between the transmit circuit and the receive circuit. The phase-shifted first portion may be combined with the second portion to reduce or substantially eliminate an insertion loss caused by the isolation circuit.