Mobile Radio Antenna Spacer Alignment
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In RF engineering, particularly in mobile communications antennas, screw connections often result in unacceptable tolerance errors leading to unwanted intermodulation products due to non-uniform contact points and material pairing issues, which existing methods fail to adequately address.
Innovation Solution
A mobile communications antenna design utilizing bush-shaped spacers with a small amount of play, pre-fitted without high press-fit forces, to ensure optimal positioning and prevent intermodulation by using a spacer with an insertion portion and retaining portion that engages in an undercut, allowing for captive positioning and reducing deformation during assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If press nuts or press-fit bushes are used to pre-fit components for screw connections, then assembly can be performed in stages with multiple components, but very small inclined angles are caused leading to non-uniquely reproduced contact points and unwanted intermodulations
Solution Approach 1:
The patent introduces a specially designed spacer as an intermediary component between the reflector and cover. This spacer features a conical insertion portion that forces precise alignment during assembly, eliminating the tolerance accumulation problems caused by press-fit components. The conical geometry acts as a mechanical mediator that ensures unique, reproducible contact points while still allowing staged assembly operations.
Solution Approach 2:
The invention changes the geometric parameters of the connection system by introducing a conical insertion portion with a specific angle (5°-15°). This parameter change transforms the assembly process from one relying on tight press-fits to one guided by angular convergence, which naturally self-aligns components and eliminates inclined angle errors that cause intermodulation.
2Strength
If multiple screws (30-40 screws) are used to fix components together, then rigid connection is achieved, but surface damage is caused to electrically conductive coatings and metal surfaces leading to modified contact conditions and intermodulations
Solution Approach 1:
The patent applies preliminary alignment action through the conical insertion portion of the spacer before the actual screw fixation occurs. The conical geometry pre-establishes the correct spatial relationship and contact points between components, ensuring that when screws are later inserted, they engage at precisely defined locations without causing surface damage from misalignment or forced assembly.
Solution Approach 2:
The spacer serves as a protective intermediary that prevents direct damaging contact between the reflector and cover during assembly. Its conical insertion portion guides the assembly process and distributes forces evenly, preventing the surface damage to conductive coatings that occurs when multiple screws are forced into tightly toleranced holes without preliminary alignment.
Data Source
AI summary
An improved mobile radio antenna suited to radio-frequency connections has a base module that comprises a plurality of mounting sections that each contain an internally threaded hole. An attachment module has mounting sections with through-holes made therein. Spacers are used between the base module and the attachment module. An undercut is provided in the through-hole in the attachment module such that the diameter of the through-hole merges into the undercut with a greater diameter in the plug-in direction, or is provided in a second electrically conductive spacer that is positioned on the attachment module on the side that is opposite the first spacer, the second spacer having a spacer hole with an undercut that broadens in the plug-in direction.