Floating Conductors Suppress Capacitive Coupling in RF Switches
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Solution Overview
Problem
Miniaturization of radio frequency switch circuits in mobile communication devices leads to increased capacitive coupling, resulting in signal leakage and degradation due to the overlapping of elements and interconnections, which complicates the simultaneous switching of multiple radio frequency signals.
Innovation Solution
The RF switch circuit is configured with a plurality of floating conductors between the through-switches and shunt switches and the signal interconnections, dispersing capacitive coupling in a direction parallel to the semiconductor layer, thereby reducing signal leakage and degradation while allowing for miniaturization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the RF switch circuit is miniaturized, then the device size is reduced, but capacitive coupling between internal elements increases causing signal leakage and degradation
Solution Approach 1:
A ground conductor is introduced as an intermediary element positioned between the signal interconnection and the through-switch/shunt switch. This ground conductor acts as a shield that reduces capacitive coupling between the signal path and switching elements, thereby mitigating signal leakage and degradation while allowing the RF switch circuit to maintain miniaturized dimensions
2Volume of moving object
If the RF switch circuit is miniaturized, then the device size is reduced, but isolation characteristics deteriorate due to overlapping elements
Solution Approach 1:
The ground conductor serves as a shielding intermediary that electrically isolates the signal interconnection from the through-switch and shunt switch. By positioning the ground conductor between these elements, the patent improves isolation characteristics preventing unwanted signal paths while maintaining the compact circuit layout required for miniaturization
3Volume of moving object
If the RF switch circuit is miniaturized, then the device size is reduced, but breakdown voltage characteristics deteriorate due to increased capacitive coupling
Solution Approach 1:
The ground conductor positioned between the signal interconnection and switching elements reduces capacitive coupling, which directly improves breakdown voltage characteristics. By minimizing parasitic capacitance effects through the shielding ground conductor, the circuit can withstand higher voltage stresses without breakdown while maintaining miniaturized dimensions
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
This configuration effectively suppresses capacitive coupling, improving isolation and breakdown voltage characteristics, and maintaining excellent miniaturization of the RF switch circuit, thereby preventing signal degradation and enhancing the performance of radio frequency signals.
Implementation Method 1
miniaturization of these radio frequency switch circuits disadvantageously increases the capacitive coupling between internal elements, interconnections, and the like, thus disadvantageously resulting in worse leakage and degradation of radio frequency signals
Data Source
AI summary
A semiconductor device includes a field effect transistor formed on a semiconductor layer. The field effect transistor can be used for passing or blocking a radio frequency signal. A signal interconnection wiring is above the field effect transistor in a first direction. A plurality of conductors, which are in electrically insulated from each other and other elements in the device, is between the field effect transistor and the signal interconnection wiring in the first direction. A length, in a second direction, of each floating conductor is less than a width, in the second direction, of a gate of the field effect transistor. Here, the second direction is parallel to the plane of the semiconductor layer and perpendicular to a gate length direction of the field effect transistor.