Balanced Duplexer Circuit With Non-Reciprocal Phase Isolation
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Solution Overview
Problem
Current wireless communication systems using frequency division duplex (FDD) transceivers are limited by narrow bandwidth for transmitting and receiving signals, requiring separate cables and increasing device size, which restricts the incorporation of additional circuitry.
Innovation Solution
A full-duplex transceiver design with two circuit paths and an isolation circuit, utilizing a balun and non-reciprocal phase shifters to enable simultaneous transmission and reception of signals at the same frequency range, improving isolation and reducing the need for separate cables.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If frequency division duplex (FDD) transceiver is used, then isolation between transmitter and receiver is achieved, but bandwidth is limited to narrow ranges (about 20 MHz for transmission and 20 MHz for reception)
Solution Approach 1:
The patent divides the signal path into two separate circuit paths (first circuit path and second circuit path) between the antenna and isolation circuit, allowing different signal frequencies to be routed through different paths. This segmentation enables full-duplex operation with wider bandwidth by preventing frequency-based interference while maintaining isolation between transmit and receive signals.
2Reliability
If frequency division duplex (FDD) transceiver is used, then transmitter and receiver isolation is maintained, but device size increases due to requiring at least two separate cables
Solution Approach 1:
The patent merges the transmit and receive signal paths into a single cable connection by implementing full-duplex operation over one cable. The isolation circuit maintains separation between transmit and receive signals electrically while both signals share the same physical cable, reducing the cable count from two to one and decreasing device size.
Solution Approach 2:
The single cable serves multiple functions by carrying both transmit and receive signals simultaneously. The isolation circuit enables this multi-functionality by providing electrical separation and preventing interference, allowing one cable to replace what would traditionally require two separate cables.
3Reliability
If two separate cables are used for transmission and reception in FDD transceiver, then signal isolation is achieved, but additional circuitry integration is prevented due to space constraints
Solution Approach 1:
The patent combines multiple signal paths into a single cable interface, freeing up physical space within the device. This space can then be utilized to integrate additional circuitry such as impedance tuners, phase shifters, and other functional blocks that enhance device capability without increasing the cable count.
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 doubles the available bandwidth for transmitting and receiving signals, reduces device size by allowing a single cable for simultaneous transmission and reception, and maintains or improves isolation between transmitter and receiver circuits.
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
the balun may receive an input signal (e.g., traveling in a first direction) and output two output signals of opposite polarities (e.g., being 180 degrees out of phase from one another), each having half the power of the input signal
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.