Canted Coil Spring Contacts for High Frequency Coaxial Connectors
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Solution Overview
Problem
High frequency miniature coaxial connectors, such as SMB and SMA, face limitations in frequency range due to structural mismatches and discontinuities, particularly at higher frequencies, leading to signal leakage and poor VSWR, which restricts their operating range and requires additional components for EMI shielding and engagement.
Innovation Solution
The use of miniature canted coil spring contacts that serve as both EMI shielding and engagement means, minimizing structural mismatches and discontinuities, and allowing for a compact design without extra components, thereby enhancing the continuous characteristic impedance and VSWR, and extending the operating frequency range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If SMB connector with metal collet is used for quick connection, then ease of operation is improved, but working frequency range is limited due to EM wave leakage through slots
Solution Approach 1:
The patent merges the EMI shielding function and engagement function into a single integrated component - the canted coil spring contact. This eliminates the need for separate collet structures with slots that cause EM wave leakage, while maintaining quick connection capability through the spring's inherent engagement mechanism.
Solution Approach 2:
The canted coil spring contact serves multiple functions simultaneously: it provides EMI shielding, enables quick engagement/disengagement, maintains characteristic impedance continuity, and ensures reliable electrical contact. This multi-functionality resolves the contradiction by eliminating the need to choose between connection speed and signal quality.
2Reliability
If SMA connector with threaded coupling is used for high frequency signal propagation, then working frequency range is improved, but device complexity increases due to additional threading structure
Solution Approach 1:
The patent extracts the threading mechanism from the engagement structure, replacing it with a simpler canted coil spring contact that engages through a groove. This maintains the electromagnetic shielding and signal propagation qualities of threaded connectors while eliminating the mechanical complexity of threads.
Solution Approach 2:
The invention changes the engagement parameter from threaded mechanical interference to spring-based elastic contact. The canted coil spring's engagement force and positioning are controlled by its geometric parameters (coil diameter, pitch, cant angle) rather than thread pitch and depth, simplifying the overall structure while maintaining high frequency performance.
3Object-affected harmful factors
If separate EMI shielding and engagement components are used, then EMI shielding effectiveness is improved, but device complexity and size increase
Solution Approach 1:
The patent combines the EMI shielding function and engagement function into a single integrated component - the canted coil spring contact. This eliminates the need for separate collet structures with slots that cause EM wave leakage, while maintaining quick connection capability through the spring's inherent engagement mechanism.
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 implementation of miniature canted coil spring contacts improves signal propagation by reducing unwanted EM wave leakage, achieving a higher operating frequency range and easier engagement/disengagement, while reducing the connector's size and complexity, with a VSWR not exceeding 2.5 and a compact design similar to a coin cell battery length.
Implementation Method 1
the use of miniature canted coil spring contacts for EMI shielding improves the continuity of the characteristic impedance of the connector throughout as compared to that of the SMB connector by minimizing structural mismatches and discontinuities
Implementation Method 2
a canted coil spring contact with certain structural features requires only a small groove within a first outer conductor of a first connector element (male or female) for it to be retained and can quickly establish engagement with a second outer conductor of a second connector element (male or female)
Data Source
AI summary
Coaxial connecting devices used for transmitting high frequency electrical signals having two connector elements of generally cylindrical profile, and wherein each of the connector elements has an inner conductor, an insulator, and an outer conductor. In one of the two connector elements that may be of a male or a female orientation has two canted coil spring contacts where at least one of a first spring contact can be retained within at least one first spring groove within a second inner conductor and at least one of a second spring contact is retained within at least one second spring groove within a second outer conductor. The at least one second spring contact can be used as a simultaneous EMI shielding contact and latching, locking, or both latching and locking device.