GaN Traveling-Wave Switch Layout for W-Band Isolation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Gallium nitride (GaN) devices face challenges in achieving high isolation and low insertion loss in ultrahigh frequency bands, particularly in military components, due to their parasitic components and high on-resistance, which limits their use in systems requiring high isolation and frequency beyond 30 GHz.
Innovation Solution
A traveling wave switch design utilizing GaN transistors connected in parallel with specific transmission line configurations, including λ/4 length and impedance, to optimize the on-off states of GaN transistors as resistances and capacitors, enhancing isolation and reducing insertion loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If GaN devices are used to achieve high breakdown voltage, then high power switching capability is improved, but parasitic components and on-resistance increase causing degraded switching function
Solution Approach 1:
The patent divides the switching function into two separate structures: a parallel switch configuration (Q3, Q4) for high-power handling and a series switch configuration (Q1, Q2) for signal isolation. This segmentation allows each structure to optimize its specific function rather than requiring a single device to fulfill both contradictory requirements.
Solution Approach 2:
The patent introduces inductors (L1, L2) as intermediary elements to compensate for the parasitic components inherent in GaN devices. These inductors act as mediators that counterbalance the parasitic effects, enabling the GaN devices to function effectively despite their intrinsic limitations.
2Speed
If parallel switch structure is used to reduce parasitic components, then operating frequency is improved, but isolation between ports deteriorates
Solution Approach 1:
The patent segments the switching system into parallel and series components, where the parallel section (Q3, Q4) handles high-frequency switching with reduced parasitics, while the series section (Q1, Q2) provides the necessary port isolation. This functional segmentation resolves the contradiction between frequency performance and isolation requirements.
3Reliability
If series switch structure is used to improve isolation, then port isolation is improved, but parasitic components and insertion loss increase
Solution Approach 1:
The patent uses inductors (L1, L2) as intermediary compensation elements that counteract the parasitic components in the series switch structure. These inductors reduce the net parasitic effect, allowing the series configuration to provide isolation without excessive insertion loss.
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 design achieves excellent insertion loss and isolation characteristics, enabling efficient operation in ultrahigh frequency bands like the W-band without the need for additional limiters, thereby enhancing the performance of ultrahigh frequency circuits.
Implementation Method 1
a first transmission line which is provided between the input terminal and a node on the path to which a first transistor is connected
Implementation Method 2
The first transmission line and the second transmission line may have a length of λ/4
Data Source
AI summary
Provided is a switch having a structure having an excellent isolation characteristic even without a limiter in an ultrahigh frequency hand used for a military component. A switch according to an embodiment of the present invention comprises: multiple transistors which are connected in parallel to a path from an input terminal toward an output terminal and perform switching; and a first transmission line provided between the input terminal and a node on a path to which a first transistor is connected. By the present invention, switching can be performed in an ultrahigh frequency such as W-band while a GaN transistor is used, an insertion loss is low, an isolation characteristic is excellent, and eventually efficiency of an ultrahigh frequency circuit can be further enhanced.