Duplexer Resonator Ground Coupling Eliminates Phase Shifter
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Solution Overview
Problem
Existing duplexers for mobile communication devices face interference issues between transmit (Tx) and receive (Rx) filters due to the small frequency difference between signals, requiring additional components like phase shifters to prevent interference, which increases processing complexity and assembly costs.
Innovation Solution
A duplexer design that uses two band-pass filters (BPFs) with specific resonance circuits and inductors to maintain electrical isolation between Tx and Rx filters without the need for a phase shifter, ensuring the Rx filter is in a line-open state for the Tx frequency band and vice versa, thereby preventing interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a phase shifter is added to prevent interference between Tx and Rx filters, then interference prevention is improved, but device complexity and assembly cost increase
Solution Approach 1:
The patent extracts and eliminates the phase shifter component from the duplexer system. By redesigning the filter structure to use resonators with coupled ground electrodes, the invention removes the need for additional phase shifting components, thereby reducing device complexity and assembly cost while maintaining interference prevention capability through the inherent electromagnetic coupling characteristics of the resonator design
Solution Approach 2:
The patent merges the phase shifting function into the filter structure itself. By using resonators where ground electrodes are coupled to each other through capacitance, the filter structure simultaneously performs both filtering and phase shifting functions, eliminating the need for separate phase shifter components and reducing overall device complexity
2Reliability
If a phase shifter is added to prevent interference between Tx and Rx filters, then interference prevention is improved, but assembly cost increases
Solution Approach 1:
The patent extracts and eliminates the phase shifter component from the duplexer system. By redesigning the filter structure to use resonators with coupled ground electrodes, the invention removes the need for additional phase shifting components, thereby reducing device complexity and assembly cost while maintaining interference prevention capability through the inherent electromagnetic coupling characteristics of the resonator design
Solution Approach 2:
The patent merges the phase shifting function into the filter structure itself. By using resonators where ground electrodes are coupled to each other through capacitance, the filter structure simultaneously performs both filtering and phase shifting functions, eliminating the need for separate phase shifter components and reducing overall device complexity
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 design effectively prevents interference between Tx and Rx filters, reduces processing complexity, and lowers assembly costs by eliminating the need for additional components like phase shifters, while maintaining efficient filtering characteristics across different frequency bands.
Implementation Method 1
when the electrical energy is applied to the upper and lower electrodes of the FBAR and an electric field temporally changing is induced in the piezoelectric layer, resonance occurs since the piezoelectric layer causes the piezoelectric effect which changes the electric energy into mechanical energy of an acoustic waveform
Implementation Method 2
resonance occurs since the piezoelectric layer causes the piezoelectric effect which changes the electric energy into mechanical energy of an acoustic waveform. In this case, since the FBAR passes only a signal within a specific band centering on the generated resonant frequency
Data Source
AI summary
A duplexer is provided. The duplexer includes a first band pass filter (BPF) coupled to a first signal port and a second signal port; and a second BPF coupled to the first signal port and a third signal port, each of the first BPF and the second BPF including a first resonance circuit which comprises a plurality of first resonators coupled in series; a second resonance circuit which comprises a plurality of second resonators coupled in series; and a third resonance circuit which comprises a plurality of third resonators coupled in parallel and formed in divided lines coupling the first and second resonance circuits.