Front End Module With Switched Notch Filters for 5G Bandwidth
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional SAW and BAW filters struggle to support the broader bandwidths required for 5G frequency bands n77, n78, and n79 due to their narrow frequency gaps between resonance and anti-resonance frequencies, making it difficult to achieve the necessary attenuation and broad pass bands for carrier aggregation and coexistence with LTE and Wi-Fi communications.
Innovation Solution
A front end module is designed with a base filter and two notch filters, where the stop bands of the notch filters overlap the pass band of the base filter, utilizing LC resonance circuits and either SAW or BAW resonators to provide selective attenuation and broad frequency coverage, including the use of a switch to connect the notch filters to the base filter for improved attenuation properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional SAW filter or BAW filter is used, then narrow frequency gap between resonance and anti-resonance is achieved, but broad bandwidth and high attenuation for 5G bands cannot be supported
Solution Approach 1:
The filter system is divided into a base filter and multiple notch filters with different stop bands. Each notch filter targets specific frequency ranges, allowing the system to achieve both narrow frequency selectivity for certain bands and broad bandwidth support for 5G bands n77, n78, and n79 by selectively connecting appropriate notch filters.
Solution Approach 2:
The switch enables dynamic reconfiguration of the filter system by selectively connecting different notch filters to the base filter. This dynamic adjustment allows the system to adapt to different 5G frequency bands and operational requirements, providing both narrow frequency selectivity when needed and broad bandwidth support when required.
2Device complexity
If conventional SAW filter or BAW filter is used, then simple structure is maintained, but inability to support broader bandwidths for carrier aggregation occurs
Solution Approach 1:
The filter system is segmented into a base filter and multiple notch filters, each with specific functions. This segmentation allows the system to support carrier aggregation across multiple 5G bands by selectively connecting appropriate notch filters to the base filter through the switch, achieving broad bandwidth support without excessive complexity.
Solution Approach 2:
The base filter serves as a universal foundation that can work with different notch filters to support multiple 5G frequency bands (n77, n78, n79) and carrier aggregation scenarios. This multi-functional design allows a single base filter structure to adapt to various bandwidth requirements.
3Device complexity
If single notch filter is used with base filter, then simple configuration is maintained, but insufficient attenuation and pass band coverage for all 5G bands is achieved
Solution Approach 1:
The filtering function is segmented across multiple notch filters, each providing attenuation for specific frequency ranges. By selectively connecting appropriate notch filters to the base filter through the switch, the system achieves sufficient attenuation and pass band coverage for all 5G bands n77, n78, and n79 while maintaining reasonable configuration 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
The solution achieves high-performance bandwidth and attenuation properties, securing 30 dB or higher attenuation in specific bands for carrier aggregation and coexistence with LTE and Wi-Fi communications, while maintaining low insertion loss in the pass bands, effectively addressing the limitations of conventional filters.
Implementation Method 1
The base filter may include at least one parallel LC resonance circuit disposed on a series end between an input terminal and an output terminal, and at least one series LC resonance circuit disposed on a shunt end between the series end and a ground
Implementation Method 2
The at least one resonator may include either one or both of a surface acoustic wave (SAW) resonator and a bulk acoustic wave (BAW) resonator
Implementation Method 3
The at least one resonator may include either one or both of a surface acoustic wave (SAW) resonator and a bulk acoustic wave (BAW) resonator
Data Source
AI summary
A front end module includes a base filter configured to operate as a bandpass filter passing a pass band of an input radio frequency signal; a switch connected to the base filter, and a first notch filter and a second notch filter selectively connected to the base filter through the switch, wherein a stop band of the first notch filter and a stop band of the second notch filter overlap the pass band of the base filter in a band equal to or higher than a center frequency of the pass band of the base filter.