MEMS Switch Contact Element Segmentation for Low Insertion Loss
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current broadband RF MEMS switches face challenges in achieving low insertion loss and high isolation at ultra-high frequencies, with existing devices typically having insertion losses of around 0.6 dB and return losses of approximately 13 dB at 40 GHz.
Innovation Solution
The development of a MEMS switch with a contact element having an electrically-insulative and conductive portion, suspended within a ground housing with air gaps, allowing for movement between isolated and contacting positions, and fabricated using multiple layers of electrically-conductive material to minimize insertion loss and maximize isolation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If traditional MEMS switch designs are used, then device miniaturization is achieved, but insertion loss increases at ultra-high frequencies
Solution Approach 1:
The contact element is divided into three distinct portions: a first electrically insulative portion, a middle electrically conductive portion, and a second electrically insulative portion. This segmentation allows the conductive portion to make contact with signal conductors while the insulative portions prevent contact with ground conductors, thereby reducing signal loss and improving insertion loss performance at ultra-high frequencies while maintaining miniaturization.
Solution Approach 2:
Different portions of the contact element have different electrical properties (conductive vs. insulative) tailored to specific functional requirements. The middle portion is conductive to establish signal paths, while the end portions are insulative to maintain isolation from ground, optimizing local electrical characteristics to minimize overall insertion loss.
2Ease of manufacture
If conventional switch structures are employed, then manufacturing simplicity is maintained, but isolation performance deteriorates at high frequencies
Solution Approach 1:
The contact element's three-portion structure enables simultaneous achievement of high isolation and ease of manufacture. The insulative end portions naturally prevent parasitic coupling to ground conductors, while the middle conductive portion provides controlled signal contact, achieving 40 dB isolation at 40 GHz without complex additional structures.
3Device complexity
If standard contact designs are used, then device complexity is minimized, but return loss performance worsens at ultra-high frequencies
Solution Approach 1:
The contact element incorporates localized insulative portions at its ends, creating specific electrical characteristics at critical locations. This local differentiation prevents unwanted capacitive coupling between the contact element and ground conductors, improving return loss to 24 dB at 40 GHz while adding minimal structural complexity.
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 achieves significantly reduced insertion loss of approximately 0.09 dB and improved return loss of 24 dB at 40 GHz, along with maintaining high isolation, representing an 85% improvement over the best-in-class switches, while also enabling higher power-handling capabilities and linearity.
Implementation Method 1
a contact element having a first electrically insulative portion, an electrically conductive second portion, and a second electrically insulative portion
Implementation Method 2
an electrostatic actuator configured to move the contact element between the open and closed positions
Data Source
AI summary
Embodiments of switches (10) include first and second electrical conductors (34, 36) suspended within an electrically-conductive housing (28), and a contact element (16) having an electrically-conductive portion (53b) that establishes electrical contact between the first and second electrical conductors (34, 36) when the contact element (16) is in a closed position. The electrically-conductive portion (53b) is electrically isolated from a ground plane (27) of the switch (10) by adjacent electrically-insulative portions (53a, 53c) of the contact element (16).