Cross-Coupled Differential Switch Circuit for Wideband Isolation
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Solution Overview
Problem
Existing high-frequency systems face challenges in achieving wide frequency band isolation during switching operations due to parasitic capacitance (Coff) of series-connected switches, which leads to signal leakage and limited isolation bandwidth.
Innovation Solution
A reconfigurable circuit using a cross-coupled switch configuration with cross-coupled capacitors or switches is implemented to provide isolation across a wide frequency band, minimizing additional circuitry and avoiding insertion loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a switch is used to change circuit state, then reconfigurability is achieved, but parasitic capacitance causes signal leakage and limited isolation bandwidth
Solution Approach 1:
The patent introduces an additional switch as an intermediary element connected in parallel with the main switch. This intermediary switch, when turned on, provides an alternative current path that compensates for the parasitic capacitance effect of the main switch, thereby improving isolation performance without sacrificing reconfigurability
Solution Approach 2:
The patent applies preliminary anti-action by pre-configuring the parallel switch circuit to counteract the harmful effect of parasitic capacitance before it degrades isolation performance. The parallel switch is designed to activate in conjunction with the main switch, proactively neutralizing the leakage effect rather than reacting to it after occurrence
2Reliability
If an additional inductor is used to offset parasitic capacitance, then isolation is improved, but device area increases
Solution Approach 1:
The patent substitutes the mechanical/physical inductor component with an electronically-controlled switch-based isolation mechanism. Instead of using a passive inductor that occupies physical space, the invention uses an actively controlled parallel switch that achieves the same isolation effect through electronic switching, thereby reducing device area while maintaining isolation performance
3Reliability
If LC resonance is used to compensate parasitic capacitance, then isolation bandwidth is improved, but circuit complexity increases
Solution Approach 1:
The patent changes the operational parameters by using a switch-based mechanism that can be controlled through voltage levels rather than relying on fixed LC resonance frequencies. This allows dynamic adjustment of isolation characteristics and simplifies the circuit by eliminating the need for precise inductor-capacitor resonance tuning, thereby reducing circuit complexity while maintaining wide isolation bandwidth
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
The proposed solution effectively achieves high isolation across a wide frequency band without significant additional circuitry, addressing the limitations of existing technologies in multi-band, multi-mode operations.
Implementation Method 1
a method of providing isolation using a resonance effect by using an additional inductor
Data Source
AI summary
A reconfigurable circuit for differential network includes: first circuit which is a two-port differential circuit; first cross-coupled switch circuit connected to first port on one side of the first circuit in parallel; and second circuit connected to second port on the other side of the first cross-coupled switch circuit in series. The first cross-coupled switch circuit includes: first-series switch disposed between and connected to first terminal of the first port and first terminal of the second port in series; second-series switch disposed between and connected to second terminal of the first port and second terminal of the second port in series; first cross-coupled element disposed between and connected to the first terminal of the first port and the second terminal of the second port; and second cross-coupled element disposed between and connected to the second terminal of the first port and the first terminal of the second port.