Higher-Order Load Circuit for Multi-Band RF Noise Filtering
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Solution Overview
Problem
Current radio filtering technologies are bulky, costly, and not integrated with the rest of the radio equipment, struggling to efficiently manage noise within and outside the transmit band, especially as future cellular standards support multiple bands.
Innovation Solution
A higher-order load circuit is implemented in filters like N-path and trans-impedance filters, providing low impedance for unwanted signals and high impedance for desired signals, allowing for tunable filtering across multiple bands.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional filters are used for band selection and noise filtering, then filtering performance is achieved, but the device becomes bulky and costly
Solution Approach 1:
The patent merges the filter circuitry directly into the radio frequency front end, combining functions that were previously separate. The higher-order load circuit is integrated with the N-path filter or trans-impedance filter, eliminating the need for separate traditional filters and reducing overall device bulkiness while maintaining filtering performance
Solution Approach 2:
The patent replaces traditional mechanical or discrete filter components with an integrated higher-order load circuit implemented through electronic circuitry. This substitution uses active electronic elements (amplifiers, capacitors, resistors) to achieve filtering functionality that was previously requiring bulky passive components
2Reliability
If multiple filters are implemented for each band, then noise filtering capability is improved, but device complexity and cost increase
Solution Approach 1:
The higher-order load circuit serves multiple functions simultaneously: it provides noise filtering, band selection, and impedance transformation. This multi-functional design eliminates the need for separate filters for each band, reducing device complexity while maintaining comprehensive noise filtering capability across all supported bands
Solution Approach 2:
The patent combines multiple filtering functions into a single higher-order load circuit that can be shared across multiple bands. Instead of implementing separate filters for each band, the integrated circuit handles filtering for all bands, significantly reducing the number of components and overall device complexity
3Object-affected harmful factors
If narrowband filters are used to comply with noise requirements, then noise radiation control is improved, but the filter becomes less effective for broader frequency bands
Solution Approach 1:
The higher-order load circuit provides dynamic impedance characteristics that can be tuned to provide low impedance at unwanted frequencies and high impedance at desired frequencies. This dynamic behavior allows the circuit to effectively suppress noise radiation across multiple frequency bands while maintaining adaptability to different operating conditions and band requirements
Data Source
AI summary
Methods and apparatus, including computer program products, are provided for filtering. In some example embodiments, there is provided an apparatus including a first differential amplifier including a first positive input, a first negative input, and a first output, wherein the first positive input is connected to the first output via at least a first capacitor, and wherein the first negative input is connected to the first output via at least a first resistor; and a second differential amplifier including a second input, a third input, and a second output, wherein the second input is connected to the second output via at least a third resistor, wherein the third input is connected to the second output via at least a second capacitor, and wherein an input is connected to the first positive input and the second input via at least a third capacitor. Related apparatus, systems, methods, and articles are also described.