Diode-Connected RF Switch Topology for Low Loss and Isolation
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Solution Overview
Problem
High frequency switches face challenges in simultaneously achieving low insertion loss and excellent isolation characteristics, which are essential for supporting multiple frequency bands in wireless communications.
Innovation Solution
A high frequency switch design that incorporates diode-connected field effect transistors (FETs) and bipolar junction transistors (BJTs) to control signal flow, with diode units connected to the control terminals of switching devices to enable or block high frequency signals, thereby reducing resistance and increasing capacitance for improved performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional switching devices are used in high frequency switches, then the device structure is simple, but insertion loss is high and isolation characteristics are poor
Solution Approach 1:
The patent combines multiple switching devices (first switching device, second switching device, third switching device, and fourth switching device) into an integrated switching system with interconnected control terminals. This merging approach allows the system to achieve low insertion loss through coordinated operation while managing complexity through systematic design rather than simple individual components
Solution Approach 2:
The control terminals of the switching devices are designed to serve multiple functions: they control both the switching action and the isolation characteristics simultaneously. The interconnection of control terminals allows a single control signal to manage multiple switching functions, reducing the need for separate control mechanisms and thereby lowering insertion loss without proportionally increasing complexity
2Reliability
If conventional switching devices are used in high frequency switches, then the device structure is simple, but isolation characteristics are poor
Solution Approach 1:
The patent merges multiple switching devices with interconnected control terminals to create a system that achieves excellent isolation characteristics. The combination of four switching devices working in coordination provides superior isolation between different frequency bands compared to conventional single or dual-switch designs, while the systematic interconnection manages the complexity through unified control architecture
Solution Approach 2:
The control terminals act as intermediaries that coordinate the operation of multiple switching devices. By interconnecting the control terminals, the system achieves precise control over signal routing and isolation without requiring complex individual control circuits for each switching device, thereby improving reliability while keeping the overall structure manageable
Data Source
AI summary
There is provided a high frequency switch including: a first signal transferring unit including a plurality of first switching devices and at least one first diode device individually connected to control terminals of the plurality of first switching devices to enable or block signal flow between a common port transmitting and receiving a first high frequency signal and a first port inputting and outputting the first high frequency signal; and a second signal transferring unit including a plurality of second switching devices and at least one second diode device individually connected to control terminals of the plurality of second switching devices to enable or block signal flow between the common port transmitting and receiving a second high frequency signal and a second port inputting and outputting the second high frequency signal.