RF Switch Circuit Layout With Fewer Crossovers and Lower Insertion Loss
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Solution Overview
Problem
Radio frequency (RF) switches with multiple transmission paths experience significant signal quality degradation due to the increased number of crossovers, which result in higher insertion loss.
Innovation Solution
A switch circuit structure and layout system that reduces the number of crossovers by dividing switch paths into sets based on input terminals and optimizing the layout to minimize crossovers, using a processor and memory to execute a layout method that updates the circuit settings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple transmission paths are used in RF switches, then signal routing capability is improved, but the number of crossovers increases resulting in higher insertion loss
Solution Approach 1:
The patent utilizes multi-layer PCB structure to route transmission paths on different planes, allowing paths that would otherwise cross on the same layer to be separated in the vertical dimension. Common paths are routed on one layer while private paths are routed on different layers, eliminating crossovers and reducing insertion loss while maintaining the multi-path routing capability.
2Device complexity
If common paths are shared among multiple input terminals, then circuit complexity is reduced, but crossovers increase causing signal quality degradation
Solution Approach 1:
The invention separates common paths and private paths onto different PCB layers. Common paths are routed on a first layer while private paths are routed on second and third layers, allowing the paths to cross in space without actual electrical interference. This eliminates crossover-induced signal degradation while preserving the circuit sharing benefits.
Solution Approach 2:
The patent introduces an intermediate structure where common paths and private paths are coupled through vertical connections (vias) between layers. This intermediary coupling method allows the paths to interact only when needed while being physically separated during routing, preventing harmful electromagnetic coupling and crossovers.
3Area of stationary object
If non-intersecting transmission paths are routed on the same plane, then layout area is minimized, but crossovers are generated increasing insertion loss
Solution Approach 1:
The patent resolves the area-crossover conflict by utilizing the vertical dimension through multi-layer PCB construction. Transmission paths are routed on different layers when they would otherwise cross on the same layer, eliminating crossovers without requiring additional horizontal space. The compact layout is maintained while achieving crossover-free routing through layer transitions.
Data Source
AI summary
A switch device structure includes RF1-st and RF2-nd input terminals, RFA-th, RFB-th and RFC-th output terminals, P2A-th, P1B-th and P1C-th paths, and first and second common paths. The P2A-th path includes a first terminal, and a second terminal coupled to the RFA-th output terminal. The P1B-th path includes a first terminal, and a second terminal coupled to the RFB-th output terminal. The P1C-th path includes a first terminal, and a second terminal coupled to the RFC-th output terminal. The first common path is coupled to the RF2-nd input terminal and the first terminal of the P2A-th path. The second common path is coupled to the RF1-st input terminal, the first terminal of the P1B-th path, and the first terminal of the P1C-th path. The first and second common paths cross each other on different planes to form a crossover.