Duplexer-less Transceiver with Balancing Impedance Circuit
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Solution Overview
Problem
Conventional transceivers using duplexers for frequency division duplex communication face issues with internal interference, cost, and on-chip implementation challenges due to signal leakage from the transmitter to the receiver.
Innovation Solution
A duplexer-less transceiver arrangement with a balancing impedance circuit and impedance network that includes cross-connections and filters to cancel out transmitter signal contributions at the receiver input, mimicking the antenna impedance and using symmetrically arranged impedances to reduce interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a duplexer is used to prevent transmitter signal leakage to the receiver, then signal interference is reduced, but device complexity, cost, and space consumption increase
Solution Approach 1:
The patent creates a dummy load that copies the impedance characteristics of the antenna. By providing a balanced configuration where one branch connects to the antenna and the other to a dummy load with matched impedance, the transmitter signal paths are symmetrized. This copying approach eliminates the need for a duplexer while achieving the same signal isolation effect through impedance matching and differential cancellation.
Solution Approach 2:
The patent converts the harmful transmitter signal that would normally leak to the receiver into a beneficial cancellation mechanism. By intentionally allowing the transmitter signal to reach both the antenna and dummy load branches, and then using differential reception, the same signal appears as a common-mode component that can be rejected. The harmful leakage is transformed into a useful reference for cancellation.
2Adaptability or versatility
If a duplexer is used to enable full duplex communication, then simultaneous transmission and reception are achieved, but on-chip implementation becomes challenging
Solution Approach 1:
The patent segments the antenna connection into two separate branches: one connected to the antenna and another to a dummy load. This segmentation allows the transmitter output to be distributed to both paths independently. The receiver then processes these segmented paths differentially, enabling full duplex operation without requiring a bulky duplexer component that would be difficult to integrate on-chip.
Solution Approach 2:
The patent replaces the mechanical/physical duplexer component with an electrical/digital solution based on impedance matching and differential signaling. Instead of using a complex RF switch or circulator-based duplexer that is difficult to miniaturize, the invention uses purely electrical components (impedance matching circuits, differential amplifiers) that can be easily fabricated using standard semiconductor manufacturing processes.
3Object-affected harmful factors
If electrical balance with a dummy load is used to counteract transmitter contribution, then signal leakage is reduced, but impedance matching precision is difficult to maintain
Solution Approach 1:
The patent incorporates a control mechanism that monitors the impedance match between the antenna and dummy load branches and adjusts the dummy load impedance accordingly. This feedback loop ensures that even if manufacturing variations or environmental changes cause impedance drift, the system automatically compensates to maintain optimal balance. The feedback mechanism could involve measuring the differential signal quality and adjusting variable impedance elements to maximize cancellation.
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 effectively minimizes transmitter signal leakage at the receiver input, eliminating the need for duplexers and enabling efficient on-chip implementation while maintaining signal integrity across a wide bandwidth.
Implementation Method 1
a balancing impedance circuit arranged to provide an adaptive impedance arranged to mimic the impedance at the antenna port
Implementation Method 2
an impedance network differentially connecting the receiver, transmitter, antenna port and balancing impedance circuit. The impedance network includes a cross-connection
Data Source
AI summary
A duplexer-less transceiver arrangement is disclosed. The transceiver comprises a receiver configured for frequency-division duplex communication with a communication network; a transmitter configured for frequency-division duplex communication with the communication network; an antenna port for connecting to an antenna; a balancing impedance circuit arranged to provide an adaptive impedance arranged to mimic the impedance at the antenna port; and an impedance network differentially connecting the receiver, transmitter, antenna port and balancing impedance circuit, wherein the impedance network includes a cross-connection.