High Frequency Switch Using Mixed FET Body Configurations
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Solution Overview
Problem
High frequency switches using body contact-type FETs achieve good harmonic characteristics but deteriorate insertion loss characteristics, making it difficult to implement high-performance wireless communications apparatus.
Innovation Solution
A high frequency switch is configured using a combination of body contact-type FETs and floating body-type FETs, with each switching unit connected via a common port, where body contact-type FETs are connected adjacent to the common port to improve insertion loss and floating body-type FETs are connected further away to enhance harmonic characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If body contact-type FETs are used in high frequency switch, then harmonic characteristics are improved, but insertion loss characteristics are deteriorated
Solution Approach 1:
The switching unit is segmented into multiple FETs with different body contact configurations. Specifically, some FETs use body contact-type structure while others use floating body-type structure, allowing each segment to contribute different characteristics to the overall performance
Solution Approach 2:
Different FETs within the same switching unit are assigned different body contact configurations based on their local functional requirements. FETs closer to the common port use body contact-type for better insertion loss, while others use floating body-type for improved harmonic characteristics
Data Source
AI summary
There is provided a high frequency switch which is satisfactory in terms of both insertion loss characteristics and harmonic characteristics. The high frequency switch includes: a common port outputting a transmission signal to an antenna; a plurality of transmission ports each having the transmission signal input thereto; and a plurality of switching units each connected between the plurality of transmission ports and the common port to conduct or block the transmission signal from each of the transmission ports to the common port, wherein each of the switching units includes a plurality of series-connected MOSFETs formed on a silicon substrate, the plurality of MOSFETs are any one of body contact-type FETs and floating body-type FETs, and each of the switching units includes both of the body contact-type FETs and the floating body-type FETs.