Wave Separator Susceptance Tuning for Impedance Matching
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Solution Overview
Problem
Existing wave separator configurations with multiple duplexers connected to a common antenna terminal face challenges in achieving good impedance matching, leading to increased bandpass loss and return loss.
Innovation Solution
A multiplexer design incorporating multiple band pass filters with a common terminal, where specific susceptance conditions are met between filters, and the inclusion of series and parallel arm resonators, allows for optimal impedance matching and reduced bandpass loss and return loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple duplexers are connected to a common antenna terminal to configure a multiplexer or wave separator, then multi-band and multi-mode operation is achieved, but impedance matching deteriorates leading to increased bandpass loss and return loss
Solution Approach 1:
The patent applies parameter changes by carefully controlling the susceptance values of band pass filters based on their center frequencies. Specifically, the first band pass filter's susceptance is set according to the formula B(1) = B(2) × {2×f(2) - f(1)}/f(1), where B represents susceptance and f represents center frequency. This parameter optimization enables good impedance matching across multiple frequency bands while maintaining low bandpass loss and return loss, resolving the contradiction between multi-band adaptability and energy loss.
2Adaptability or versatility
If multiple duplexers are connected to a common antenna terminal, then multi-band operation is achieved, but impedance matching becomes difficult
Solution Approach 1:
The patent employs parameter changes by establishing specific mathematical relationships between the susceptance values and center frequencies of multiple band pass filters. The condition B(1) = B(2) × {2×f(2) - f(1)}/f(1) provides a precise design guideline for achieving impedance matching in multi-band wave separators, transforming the difficult impedance matching problem into a calculable parameter optimization task.
3Adaptability or versatility
If the antenna terminals of duplexers are connected to a common antenna terminal, then a multiplexer configuration is achieved, but good impedance matching cannot be obtained
Solution Approach 1:
The patent resolves the impedance matching issue in multiplexer configurations by introducing specific parameter relationships among band pass filters. By setting the susceptance of the first band pass filter according to B(1) = B(2) × {2×f(2) - f(1)}/f(1), the invention ensures reliable impedance matching across all connected duplexers, thereby improving the overall reliability of the multiplexer system while maintaining its multi-band functionality.
Data Source
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AI summary
A wave separator (1) according to the invention includes a number n (n being a natural number of 3 or larger) of band pass filters (10-40) having a number n or larger of mutually different pass bands; and a common terminal (21). Among the number n of band pass filters (10-40), for a first band pass filter that is one of a band pass filter having a center frequency of a pass band at a lowest frequency side and a band pass filter having a center frequency of a pass band at a highest frequency side, and that has a larger or equal difference in a center frequency of a pass band from an adjacent band pass filter as compared with the other band pass filter at the other of the highest or lowest frequency side, satisfies a predetermined configuration with respect to a second band pass filter having a pass band adjacent to the first band pass filter.