Electrical Balance Duplexer With Impedance Tuning for Low-Loss Isolation
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Solution Overview
Problem
Conventional duplexers, including N-Path filters and traditional electrical balanced duplexers, suffer from higher insertion loss and are sensitive to antenna impedance shifts, which degrade isolation between transmit and receive paths, and require additional band-pass filters for flexible frequency usage, increasing space and cost.
Innovation Solution
The proposed electrical balanced duplexer (EBD) employs balance-unbalance transformer circuits with impedance gradients and impedance tuners to selectively block or allow signals at specific frequencies, reducing insertion loss and eliminating the need for an active antenna replica, thereby enhancing frequency flexibility and isolation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If additional band pass filters are added to the PAD to increase flexibility for diverse frequency applications, then frequency adaptability is improved, but device area and manufacturing cost increase
Solution Approach 1:
The EBD circuit is designed to handle multiple frequency applications using a single circuit architecture. The balun circuits and impedance gradients work together to provide frequency-dependent isolation and signal routing capabilities across diverse frequency bands, eliminating the need for separate band-pass filters for each frequency application.
Solution Approach 2:
The patent utilizes impedance gradients that vary with frequency to achieve frequency-selective signal routing. By changing the impedance parameters of the balun circuits and associated components based on frequency, the system achieves adaptive frequency handling without requiring additional physical filters for each frequency band.
2Reliability
If conventional duplexers with multiple band pass filters are used to provide isolation between transmitter and receiver, then isolation performance is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent combines the isolation function and frequency routing function into a single EBD circuit architecture. The balun circuits perform both signal transformation and frequency-selective routing simultaneously, merging multiple functions that would traditionally require separate components into one integrated solution.
Solution Approach 2:
The EBD circuit serves multiple functions: it provides isolation between transmit and receive paths, routes signals based on frequency, and adapts to different frequency applications. This multi-functionality reduces the overall complexity compared to conventional duplexers that require separate components for each function.
3Adaptability or versatility
If N-Path filters or traditional electrical balanced duplexers are used, then frequency routing capability is provided, but insertion loss increases and isolation degrades due to antenna impedance shifts
Solution Approach 1:
The patent employs dynamic impedance tuning through the use of impedance gradients and可调 components. The system adapts its impedance characteristics in real-time based on the operating frequency and antenna conditions, allowing it to maintain optimal performance and minimize insertion loss across varying frequency conditions rather than relying on fixed impedance values.
Solution Approach 2:
The EBD circuit changes its electrical parameters, particularly impedance, based on frequency and operating conditions. The impedance gradients and tuning mechanisms allow the circuit to optimize its parameters dynamically, reducing insertion loss and maintaining isolation performance despite antenna impedance shifts that would degrade conventional fixed-parameter duplexers.
Data Source
AI summary
An electrical balance duplexer (EBD) may be used to isolate a transmitter and receiver that share a common antenna. By using impedance gradients to provide impedances that cause balance-unbalance transformers (balun) of the EBD to cut-off access to the common antenna rather than duplicate the antenna impedance, the EBD is balanced. Such cut-offs may have a lower insertion loss than an EBD that merely duplicates the antenna impedance to separate the differential signals of the receiver/transmitter from the common mode signal.