Coaxial Lead Assembly for RF Module Packages
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Solution Overview
Problem
Module packages in RF communication systems face limitations due to the inductive nature of their leads, which restrict operating frequency and bandwidth, and suffer from poor heat transfer leading to reliability issues, especially when mounted on printed circuit boards with mechanical tolerances causing variable parasitic inductance and thermal conductivity challenges.
Innovation Solution
A module package design incorporating a coaxial lead assembly with a dielectric structure and a central conductor surrounded by an outer conductor, formed from a multi-layer laminate structure, which reduces parasitic inductance and enhances heat transfer by providing a shielding path and improved thermal conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional RF leads are used in module packages, then the package can be manufactured with standard processes, but the parasitic inductance restricts operating frequency and bandwidth
Solution Approach 1:
The patent replaces traditional inductive RF leads with a coaxial cable assembly that uses electromagnetic field confinement between concentric conductors. This substitution transforms the mechanical lead structure into an electromagnetic field-based transmission system, eliminating parasitic inductance and enabling broader bandwidth operation while maintaining manufacturability through standard coaxial cable assemblies.
Solution Approach 2:
The patent changes the fundamental electrical parameters of the connection by transitioning from simple conductive leads to coaxial structures with controlled impedance. This parameter change allows for optimized characteristic impedance matching and eliminates the frequency-dependent inductance characteristics of traditional leads, thereby improving RF performance across wider frequency ranges.
2Ease of manufacture
If the gap between package and PCB varies due to mechanical tolerances, then manufacturing is easier, but parasitic inductance varies substantially
Solution Approach 1:
The patent replaces the mechanical lead-to-PCB connection with a coaxial cable assembly that incorporates flexible grounding structures. These structures maintain consistent electromagnetic shielding and controlled impedance despite variations in assembly gap, allowing mechanical tolerances to be accommodated without significantly affecting parasitic inductance.
Solution Approach 2:
The patent introduces flexible grounding structures as intermediaries between the coaxial cable and PCB. These structures act as mediators that maintain electrical continuity and consistent electromagnetic field confinement despite gap variations, thereby stabilizing parasitic inductance across different assembly conditions.
3Ease of manufacture
If leads are landed on organic substrate, then manufacturing is simplified, but thermal conductivity is limited causing heat dissipation issues
Solution Approach 1:
The patent employs coaxial cable assemblies with composite construction featuring inner conductors, dielectric insulation, and outer conductive shielding. This composite structure provides both electrical functionality and enhanced thermal pathways, allowing heat to conduct along the central conductor and outer shield to ground planes, thereby improving heat dissipation while maintaining integration with organic substrates.
Solution Approach 2:
The patent creates thermal pathways that replicate the electrical pathways of the coaxial structure. The outer conductor and grounding structures serve dual purposes: providing electromagnetic shielding and creating thermal conduction paths that mirror the electrical field distribution, enabling efficient heat transfer from the module package to the PCB ground planes.
4Power
If RF power increases to meet communication demands, then communication capability improves, but heat generation increases causing solder reflow and catastrophic failure
Solution Approach 1:
The patent utilizes the composite coaxial cable structure with conductive inner and outer elements separated by dielectric material. This composite design provides multiple parallel thermal conduction pathways through the conductors to ground, enabling high RF power handling while dissipating generated heat efficiently to prevent solder reflow and maintain thermal stability.
Solution Approach 2:
The patent introduces the coaxial cable assembly as an intermediary between the high-power RF module and the PCB. This intermediary structure provides both electrical connection and thermal management, conducting RF signals while simultaneously providing thermal pathways to ground planes, thereby protecting against thermal runaway and catastrophic failure.
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 coaxial lead assembly improves RF performance by reducing the impact of gap variations between the module package and the PCB, increasing bandwidth, and enhancing heat transfer, thereby improving long-term reliability and reducing the risk of catastrophic failures.
Implementation Method 1
The dielectric structure may reside between the central conductor and the outer conductor, such that the central conductor and outer conductor are isolated from one another
Implementation Method 2
The RF leads of the module package are, by nature, mostly inductive. The resultant inductance can best be described as a parasitic, which must be dealt with rather than a desired transition
Implementation Method 3
A coaxial lead assembly extends out of the housing and facilitates electrical connections with the component
Implementation Method 4
the leads are landed on an organic substrate, which has limited thermal conductivity (e.g. less than 2 W/(m*K))
Data Source
AI summary
A module package in which electronic components are packaged. The package module may comprise a base, at least one component, a housing, and a coaxial lead assembly. The component is over the base. The housing is over the base and encompasses the component. The coaxial lead assembly extends out of the housing and facilitates electrical connections with the component. The at least one coaxial lead assembly comprises a dielectric structure, a central conductor, and an outer conductor formed by a top wall extending between two side walls. The central conductor may be between the two side walls. The dielectric structure may reside between the central conductor and the outer conductor, such that the central conductor and outer conductor are isolated from one another.