Multi-band RF Circuit Antenna Swapping for Intermodulation Reduction
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Solution Overview
Problem
Current mobile communication devices face challenges in optimizing RF performance for multiple frequency bands without increasing complexity, cost, and footprint, particularly in supporting uplink carrier aggregation (ULCA) and multiple-input multiple-output (MIMO) operations due to intermodulation products between adjacent RF bands.
Innovation Solution
A multi-band RF circuit design that includes multiple antenna ports and an antenna swapping circuit, with control circuitry to selectively couple transmit and receive filters, ensuring physical separation of adjacent RF band filters to reduce intermodulation products, thereby improving RF performance without increasing complexity, cost, or footprint.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple transmit and receive filters are used to support multiple frequency bands, then RF performance for ULCA and MIMO operations is improved, but device complexity, cost, and footprint increase
Solution Approach 1:
The patent combines multiple transmit filters and receive filters into shared filter banks that can be selectively coupled to different antenna ports through an antenna swapping circuit. This merging approach allows the same physical filters to serve multiple frequency bands and multiple antenna ports, reducing the total number of filters needed while maintaining support for ULCA and MIMO operations across multiple bands
Solution Approach 2:
The antenna swapping circuit enables each antenna port to be dynamically reconfigured to work with different filter banks depending on the operating band and mode (ULCA or MIMO). This multi-functionality allows a limited set of filters to support multiple frequency bands and operational modes, reducing device complexity while maintaining broad RF performance coverage
2Area of stationary object
If transmit filters of adjacent RF bands are placed close together to reduce footprint, then device footprint is reduced, but intermodulation products between adjacent RF bands increase
Solution Approach 1:
The patent extracts the harmful intermodulation effect by physically separating transmit filters of adjacent RF bands while maintaining their logical connection through the antenna swapping circuit. This spatial extraction reduces intermodulation products by increasing physical distance between adjacent band filters, while the swapping circuit ensures proper signal routing is maintained
Solution Approach 2:
The antenna swapping circuit acts as an intermediary that manages the coupling between antenna ports and filter banks. It enables the system to selectively connect appropriate filters to appropriate antenna ports based on the operating band, allowing physical separation of adjacent band filters while maintaining functional integration through controlled switching
Data Source
AI summary
Embodiments of the disclosure include a multi-band radio frequency (RF) circuit. The multi-band RF circuit includes multiple antenna ports coupled to multiple antennas and an antenna swapping circuit coupled to the multiple antenna ports. Control circuitry in the multi-band RF circuit controls the antenna swapping circuit to selectively couple various transmit and/or receive filters with any one or more of the multiple antenna ports to support uplink carrier aggregation (ULCA) and/or multiple-input multiple-output (MIMO) operations with a minimum number of transmit and receive filters. Transmit filters of adjacent RF bands are physically separated, but disposed in proximity, in the multi-band RF circuit to help reduce intermodulation products between the adjacent RF bands during the ULCA operation. As a result, it is possible to improve RF performance of ULCA and MIMO operations, without increasing complexity, cost, and footprint of the multi-band RF circuit.