Antenna Switch With Reduced Parasitic Capacitance
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Solution Overview
Problem
Existing antenna switches experience increased insertion loss due to parasitic capacitance generated by off-state switch modules, which affects the transmission of RF signals and worsens the Voltage Standing Wave Ratio (VSWR).
Innovation Solution
The design incorporates switch modules with switch units connected in series, where at least one switch unit has a smaller width than others to reduce parasitic capacitance, with specific configurations such as fewer transistors in parallel or reduced channel width for units closest to the antenna unit, minimizing overlap area and capacitance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple switch units are connected in parallel to form switch modules, then the switching capability and reliability are improved, but the parasitic capacitance increases causing higher insertion loss
Solution Approach 1:
The patent applies local quality by making the first switch unit have a different (smaller) width compared to the second and third switch units. This localized differentiation reduces the parasitic capacitance contribution from the first switch unit, which is connected in parallel and would otherwise contribute equally to the total parasitic capacitance. The selective modification of only one switch unit's dimensions optimizes the balance between switching capability and insertion loss.
2Reliability
If switch units are designed with larger width to reduce resistance, then the conductive performance is improved, but the parasitic capacitance increases worsening the VSWR
Solution Approach 1:
The patent applies parameter changes by specifically modifying the width parameter of the first switch unit to be smaller than the other switch units. This parameter adjustment directly reduces the parasitic capacitance of the first switch unit, thereby improving the VSWR performance. The design accepts a trade-off in the conductive performance of the first switch unit while maintaining overall system reliability through the combined effect of all switch units.
Data Source
AI summary
The present invention relates to a low loss antenna switch. The antenna switch comprises a plurality of switch module and a plurality of transmitting/receiving terminals, wherein one end of each switch module is connected to an antenna unit and the other end of each switch module is connected to each transmitting and receiving end respectively. Further, each switch module comprises a plurality of switch units in series, wherein the width of at least one switch unit is smaller than other switch units of each switch module. Thus, the parasitic capacitance of the off-stage switch modules can be reduced, and VSWR (Voltage Standing Wave Ratio) of the antenna switch also can be improved.