Compact Multiband Vehicle Antenna with Nested Loads
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Solution Overview
Problem
Current vehicular antenna systems are too large and cannot efficiently operate in multiple frequency bands, which conflicts with vehicle design aesthetics and functionality.
Innovation Solution
A compact antenna device comprising a monopole antenna with symmetrical first and second loads, supported by a substrate and attached to a vehicle base, capable of operating in multiple frequency bands by utilizing a U-shaped second load as a choke to prevent current propagation and reduce cross-polarization radiation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a large antenna element is used to meet performance requirements, then the antenna can operate in multiple frequency bands, but the antenna size becomes too large for vehicle aesthetics
Solution Approach 1:
The patent implements nested loading structures where a first load is positioned within a second load, both surrounding the antenna element. This nested arrangement allows multiple loading functions to be integrated in a compact space, enabling multi-frequency operation without increasing the overall antenna profile on the vehicle surface.
Solution Approach 2:
The patent transitions from conventional linear antenna elements to a planar printed circuit board substrate with strategically positioned loads. By distributing loading elements across two-dimensional space rather than extending the antenna linearly, the design achieves multi-frequency capability while maintaining a compact footprint suitable for vehicle mounting.
2Length of stationary object
If the antenna size is reduced for aesthetic purposes, then the vehicle profile is improved, but the antenna cannot meet specified performance requirements
Solution Approach 1:
The patent applies localized loading structures at specific positions around the antenna element rather than uniformly extending the antenna. The first and second loads are strategically placed to provide targeted impedance transformation and resonance control, achieving full performance requirements through concentrated local modifications rather than overall size increase.
Solution Approach 2:
The patent combines the antenna element with multiple loading structures made of conductive materials on a substrate, creating a composite antenna system. This composite structure integrates different functional elements (radiating element, impedance transformers, resonant loads) into a unified compact design that meets performance specifications without proportionally increasing size.
3Ease of manufacture
If conventional loading structures are used, then the antenna can be manufactured, but the manufacturing complexity and cost increase
Solution Approach 1:
The patent designs the loading structures to serve multiple functions simultaneously: the first load provides impedance transformation for one frequency band while the second load handles another frequency band. This multi-functionality reduces the need for separate dedicated components, simplifying the overall manufacturing process despite the multi-frequency capability.
Solution Approach 2:
The patent replaces complex mechanical antenna structures with planar printed circuit board implementations. The loading structures are realized through printed conductive traces and geometric patterns on the substrate, substituting mechanical assembly with more manufacturable PCB fabrication processes, thereby reducing assembly complexity and improving ease of manufacture.
Data Source
AI summary
An apparatus includes an antenna (e.g., a monopole), a first load, and a second load. The antenna, which extends substantially along an axis, has a first end and a second end. The first load is coupled to the antenna at the first end, while the second load is coupled to the antenna between the first end and the second end. Both the first and second loads are symmetrical with reference to the axis. The apparatus is arranged to operate in at least two frequency bands, such as the AMPS band from about 824 MHz to 894 MHz and the PCS band from about 1850 MHz to 1990 MHz.