Multichannel Relay Assembly with In-Line MEMS Switches
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Solution Overview
Problem
Current RF switch technologies, including electro mechanical relays and MEMS switches, fail to meet the ideal specifications of high isolation, linearity, medium to high power handling, and low insertion loss over a large frequency range while also being cost-effective and easy to manufacture.
Innovation Solution
A multichannel relay assembly utilizing in-line MEMS switches with independently or simultaneously actuated actuating elements, supported by a substrate with specific capacitive couplings and anchors, to achieve improved channel isolation and insertion loss performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If electro mechanical relays are used to achieve high isolation and linearity, then switching performance is improved, but device size increases and manufacturing cost increases
Solution Approach 1:
The patent replaces traditional electro mechanical relay mechanisms with MEMS (microelectromechanical system) technology. The MEMS switches use micromechanical movement at the microscale to achieve open or short circuit states, substituting the larger-scale mechanical relay structure with a miniaturized version that maintains high isolation and linearity while reducing device size and cost.
Solution Approach 2:
The patent divides the relay assembly into multiple independent MEMS switch structures arranged in series along the RF transmission line. Each MEMS switch can be independently actuated, allowing the system to achieve high isolation through series configuration while keeping individual component sizes small. This segmentation enables parallel fabrication of multiple identical units.
2Device complexity
If p-i-n diode or GaAs FET switches are used to reduce device size, then device complexity is reduced, but isolation and linearity performance deteriorate
Solution Approach 1:
The patent merges multiple MEMS switch structures in series along the RF transmission line to achieve high isolation and linearity. By combining multiple micro-scale switches rather than using a single larger switch or semiconductor device, the system attains the performance characteristics of electro mechanical relays while maintaining the compact size advantage of MEMS technology.
3Reliability
If multiple MEMS switches are placed far from RF input to reduce coupling, then isolation is improved, but insertion loss increases due to distance
Solution Approach 1:
The patent optimizes the electrical parameters of the RF transmission line segments between the RF input and the first MEMS switch, and between successive MEMS switches. By carefully controlling characteristic impedance, electrical length, and propagation characteristics of these transmission line segments, the system achieves high isolation between channels while minimizing insertion loss through proper impedance matching and electrical length selection.
4Loss of energy
If MEMS switches are positioned close to RF input to reduce insertion loss, then energy loss is reduced, but coupling between channels increases
Solution Approach 1:
The patent employs asymmetric positioning and configuration of the MEMS switches relative to the RF input and output ports. The first MEMS switch is positioned closer to the RF input than subsequent switches, and the transmission line segments between switches have different electrical lengths. This asymmetric arrangement creates different coupling conditions for different channels, enabling high isolation while maintaining low insertion loss through differential path optimization.
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 solution provides better insertion loss, lower dispersive leakage, and lower return loss, particularly suitable for high power applications, while maintaining ease of manufacturability and cost-effectiveness.
Implementation Method 1
electrostatically control ohmic RF MEMS relay
Implementation Method 2
a substrate having a first capacitive coupling, Csub; a first actuating element and a second actuating element electrically coupled in series... the first and second actuating elements have a second capacitive coupling, Cgap
Data Source
AI summary
An ohmic RF MEMS relay includes a substrate with a capacitive coupling, Csub; two actuating elements electrically coupled in series, so as to define a channel, wherein the actuating elements are configured to be independently actuated or simultaneously operated. The actuating elements have their own capacitive coupling, Cgap; a midpoint on the channel is in electrical communication with the actuating elements; and an anchor mechanically coupled to the substrate and supporting at least one of the actuating elements. Also, an ohmic RF MEMS relay that includes an input port; a plurality of first MEMS switches that make up a first switching group in electrical communication with the input port, thereby defining a plurality of channels each leading from each of the MEMS switches; and at least one outlet port along each of the channels distal from the first switching group and in electrical communication with the input port.