Dual Antenna RF Switch Architecture for High Isolation
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Solution Overview
Problem
Wireless communications devices require RF circuitry that is low cost, small, simple, flexible, and efficient to support multiple wireless protocols while minimizing size, cost, and power consumption, especially in portable devices.
Innovation Solution
The RF circuitry includes a first and second main RF switching circuit with pairs of RF switches and shunt switches, allowing flexible switching between RF antennas and providing isolation, which enables efficient signal routing and processing while maintaining a small form factor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple RF antennas and switching circuits are used to support multiple wireless protocols, then adaptability and versatility are improved, but device complexity increases
Solution Approach 1:
The RF switching circuit is designed with multiple input ports (first RF antenna, second RF antenna) and multiple output ports (first main RF port, second main RF port) that can be dynamically configured through switching circuits. This universal design allows the same hardware to support multiple wireless protocols by reconfiguring the signal paths according to different protocol requirements, thereby achieving multi-functionality without requiring separate dedicated circuits for each protocol.
Solution Approach 2:
The RF switching circuit is divided into multiple independent switching modules (first main RF switching circuit, second main RF switching circuit), each with its own set of RF switches and shunt switches. This segmentation allows each module to be independently controlled and optimized, reducing the overall complexity by breaking down the complex multi-protocol support function into manageable, modular switching units that can be configured as needed.
2Adaptability or versatility
If RF switching circuits with multiple switches are used to provide flexible signal routing, then adaptability is improved, but insertion loss increases
Solution Approach 1:
Shunt switches are introduced as intermediary elements connected to ground between the series RF switches. These shunt switches act as mediators that can divert unwanted signals to ground, improving isolation between different signal paths. By providing an intermediate grounding path, the shunt switches enable better signal routing control without requiring additional series switches that would increase insertion loss, thus maintaining energy efficiency while achieving flexible routing.
3Reliability
If isolation between RF antennas is improved using additional switching elements, then signal quality is improved, but device complexity and cost increase
Solution Approach 1:
The circuit design merges multiple functions into a single integrated switching module. Each main RF switching circuit combines series RF switches for signal path selection with shunt RF switches for isolation, allowing both signal routing and isolation functions to be achieved within the same modular structure. This merging reduces overall device complexity by eliminating the need for separate isolation circuits, as the shunt switches inherently provide both isolation and grounding functions simultaneously.
Solution Approach 2:
The RF switches in the circuit are designed to perform multiple functions: series switches provide both signal path selection and isolation, while shunt switches provide both grounding and isolation. This multi-functional design reduces the total number of switches required compared to dedicated single-function circuits, thereby reducing device complexity and cost while maintaining high isolation between RF antennas for improved signal quality.
Data Source
AI summary
RF circuitry, which includes a first main RF switching circuit and a second main RF switching circuit, is disclosed. The first main RF switching circuit is capable of providing an RF signal path between a first main RF port and a first selected one of a first RF antenna and a second RF antenna. The second main RF switching circuit is capable of providing an RF signal path between a second main RF port and a second selected one of the first RF antenna and the second RF antenna. The first main RF switching circuit includes a first pair of RF switches coupled in series between the first RF antenna and the first main RF port; a second pair of RF switches coupled in series between the second RF antenna and the first main RF port; a first shunt RF switch; and a second shunt RF switch.