RF Multiplexer With Electromagnetically Coupled LC Resonators
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Solution Overview
Problem
Conventional RF filtering circuitry faces limitations in bandwidth and quality factor, leading to poor isolation between frequency bands, which is problematic for modern wireless communications devices that require wider bandwidths and carrier aggregation configurations.
Innovation Solution
The RF multiplexer circuitry incorporates electromagnetically coupled LC resonators to enhance bandwidth and quality factor, with resonator control circuitry adjusting capacitances for improved filter responses in carrier aggregation modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If acoustic filtering circuitry is used to achieve high quality factor, then isolation between frequency bands is improved, but bandwidth is limited and flyback increases
Solution Approach 1:
The patent combines acoustic filtering circuitry (for high Q and isolation) with electromagnetic filtering circuitry (for wide bandwidth) into a hybrid RF filtering system. The acoustic filters handle frequency separation where high isolation is needed, while electromagnetic filters provide the broad bandwidth coverage, eliminating the trade-off between isolation and bandwidth.
Solution Approach 2:
The patent uses a composite filtering approach combining two different filtering technologies (acoustic and electromagnetic) with complementary characteristics. This composite system leverages the high quality factor of acoustic filters and the wide bandwidth capability of electromagnetic filters to achieve both high isolation and wide bandwidth simultaneously.
2Productivity
If the bandwidth of acoustic filtering circuitry is increased, then bandwidth is improved, but flyback increases and quality factor decreases
Solution Approach 1:
The patent segments the filtering function into two parts: acoustic filters responsible for maintaining high quality factor and electromagnetic filters responsible for providing wide bandwidth. This segmentation allows each filtering type to operate in its optimal performance range without compromising the other.
Solution Approach 2:
The patent introduces electromagnetic filtering circuitry as an intermediary component that bridges the bandwidth limitation of acoustic filters. The electromagnetic filters act as mediators that extend the overall system bandwidth while the acoustic filters maintain the quality factor through their high selectivity.
3Adaptability or versatility
If the number of frequency bands to be separated is increased, then adaptability is improved, but device complexity increases substantially
Solution Approach 1:
The patent employs electromagnetic filtering circuitry that can be configured to handle multiple frequency bands simultaneously through a single modular structure. This universal approach allows the same electromagnetic filter module to serve multiple bands, reducing the overall complexity compared to requiring separate acoustic filter modules for each band.
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 configuration provides sharper roll-off and increased bandwidth, reducing signal leakage and improving isolation between frequency bands, thus enhancing the performance of RF filtering circuitry in wireless communications devices.
Implementation Method 1
The first LC resonator and the second LC resonator are electromagnetically coupled such that a coupling factor between the first LC resonator and the second LC resonator is between about 1.0% and 40.0%
Implementation Method 2
first resonator circuitry coupled between the first signal path and ground... configured to allow signals within a first frequency pass band to pass between the first intermediate node and the common node
Data Source
AI summary
RF multiplexer circuitry includes a first signal path coupled between a first intermediate node and a common node, a second signal path coupled between a second intermediate node and the common node, first resonator circuitry coupled between the first signal path and ground, and second resonator circuitry coupled between the second signal path and ground. The first resonator circuitry is configured to allow signals within a first frequency pass band to pass between the first intermediate node and the common node, while attenuating signals outside of the first frequency pass band. The first resonator circuitry includes a first LC resonator. The second resonator circuitry is configured to allow signals within a second frequency pass band to pass between the second intermediate node and the common node, while attenuating signals outside of the second frequency pass band.