Diversity Fin Antenna Cross-Polarization Null Reduction
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Solution Overview
Problem
Existing antenna systems face issues with cross-polarized null conditions, leading to signal fading and noise, particularly in wireless audio devices, due to their linear polarization and requirement for multiple antennas with complex setup and orientation, which can be detuned by rain and environmental factors.
Innovation Solution
A diversity antenna system with a planar antenna and a second orthogonal antenna, such as whip antennas or an articulated log periodic dipole array, positioned in a fixed, perpendicular relationship, connected via coaxial cables to a diversity receiver, reducing cross-polarization nulls and allowing for easier setup and water resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If two separate antennas are used for diversity reception, then cross-polarization fade is reduced, but device complexity and setup complexity increase
Solution Approach 1:
The patent combines two separate antennas into a single integrated antenna assembly where two linearly polarized antenna elements are mounted on the same substrate. This integration maintains the diversity reception function while reducing the number of separate components, mounting hardware, and feedline routing requirements, thus resolving the contradiction between reliability and device complexity.
Solution Approach 2:
The integrated antenna assembly serves multiple functions: it provides both horizontal and vertical polarization reception capabilities within a single unit, acts as both the antenna element and the mounting structure, and eliminates the need for separate diversity receiver inputs. This multi-functionality reduces setup complexity while maintaining signal reception reliability.
2Reliability
If two separate antennas with divergent feedlines are used, then polarization diversity is achieved, but ease of operation and setup time deteriorate
Solution Approach 1:
The patent merges two separate antenna setups into one integrated assembly with co-located feedline connections. The two antenna elements share the same mounting substrate and have their feedlines connected to adjacent terminals on the same connector, eliminating the need for divergent cable routing and making setup significantly more convenient while preserving polarization diversity.
3Adaptability or versatility
If planar fin antennas are used for broad bandwidth operation, then frequency range is improved, but susceptibility to water detuning increases
Solution Approach 1:
The patent applies different material properties to different parts of the antenna system. The antenna elements are made from non-conductive, water-resistant materials such as fiberglass or plastic, while only the essential conductive elements are made from metal. This local differentiation of material quality reduces the overall susceptibility to water detuning while maintaining broad bandwidth operation.
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 system effectively reduces cross-polarization nulls, ensuring reliable signal reception across a wide frequency range, simplifies deployment, and maintains performance in wet conditions by using orthogonal antennas in a fixed arrangement, thereby minimizing signal loss and setup complexity.
Implementation Method 1
These fin type antennas are capable of operation over a broad bandwidth of 400 MHz to 3000 MHz or greater, and more typically operate over a one or two octave range of 400-1000 MHz, and exhibit forward gain of about 6 dB or more over the entire operating range.
Implementation Method 2
These antennas are linearly polarized, that is, they pick up or transmit RF energy on a single plane, usually a vertical plane.
Implementation Method 3
Because they are linearly polarized, a common problem in operation is a fading or reduction of signal strength when the position of the device results in a crossed polarization of the respective transmitting and receiving antennas.
Data Source
AI summary
A fin-type planar antenna and a deployable dipole antenna are combined into a system as a diversity fin antenna to reduce or eliminate cross polarization fades and dropouts common to wireless audio systems used in theatres, churches and convention centers. A dual feedline connects the diversity fin antenna system to a diversity-equipped receiver in a convenient and rapid manner. The antenna system features broad bandwidth, resistance to deep nulls or fades caused by cross polarization, and an air space dielectric covering provides resistance to detuning in the presence of rain, or touching objects.