Tunable Yagi Antenna with Spool-Based Radiator Length Adjustment
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Solution Overview
Problem
Current portable Yagi antennas require significant time and effort to adjust frequency and achieve a good feedline match, with low performance and limited power handling due to mechanical and electrical adjustments, and motor-driven inductors suffer efficiency losses as they are limited by the highest frequency they operate at.
Innovation Solution
A tunable antenna design featuring a boom with spools and non-conductive support poles, where wires are spooled and unscrewed to adjust lengths, allowing for frequency changes without disassembly, and can be configured as a Yagi or dipole antenna, with manual or motor-driven adjustment options.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If motor-driven variable inductors are used to change frequency, then frequency adjustment is automated, but efficiency losses increase due to fixed radiator length being too short for lower frequencies
Solution Approach 1:
The patent applies dynamics by making the radiator elements physically adjustable in length rather than fixed. The telescoping or extendable radiator design allows the physical length to match the electrical wavelength at different frequencies, eliminating the efficiency loss that occurs when a fixed short radiator is used at lower frequencies. This dynamic adjustment resolves the contradiction by enabling both automation and high efficiency across the frequency range.
Solution Approach 2:
The patent changes the physical parameter of radiator length to optimize performance at different frequencies. Instead of relying solely on electrical inductance adjustment, the system physically extends or retracts the radiator elements to appropriate lengths for each operating frequency, thereby maintaining high radiation efficiency while allowing automated frequency control.
2Power
If manual coil swapping is used to change frequency bands, then power handling ability is improved, but adjustment time increases significantly
Solution Approach 1:
The patent eliminates the need for manual coil swapping by implementing dynamically adjustable radiator elements that can be extended or retracted to achieve different resonant frequencies. This continuous adjustment mechanism maintains high power handling capability while reducing frequency change time from minutes to seconds, resolving the time-power handling contradiction.
Solution Approach 2:
The patent replaces the mechanical coil swapping system with an extended or telescoping radiator mechanism. Instead of manually removing and replacing inductors, the system uses a mechanical extension/retraction system for the radiators that can be controlled manually or automatically, significantly reducing adjustment time while maintaining the power handling benefits of proper impedance matching.
3Device complexity
If fixed inductor values are used, then device complexity is reduced, but adaptability to different frequencies is limited
Solution Approach 1:
The patent implements universality by designing a single antenna system with adjustable radiator elements that can operate across multiple frequency bands. The same physical structure, when extended to different lengths, serves multiple frequency purposes, eliminating the need for multiple fixed inductor configurations or separate antennas for different bands.
Solution Approach 2:
The patent uses dynamic radiator length adjustment to provide adaptability across frequency ranges without increasing device complexity. The single adjustable mechanism replaces multiple fixed configurations, allowing the antenna to be tuned to different frequencies by simply changing the physical length of the radiators rather than swapping components.
Data Source
AI summary
A tunable antenna is formed on a boom. First and a second opposed non-conductive support pole extend from a first end of the boom. Third and a fourth opposed non-conductive support pole extending from a second end of the boom. Each pole has a wire guide at its end. First and second spools are mounted near the first end of the boom. Third and fourth spools are mounted near the second end of the boom. First and second wires are spooled on the first and second spools. A third wire is spooled on the third spool and mechanically coupled to the first wire by a non-conductive cord, the first and third wires running through the first and third pole guides. A fourth wire is spooled on the fourth spool and mechanically coupled to the second wire by non-conductive cord, the second and fourth wires running through the second and fourth pole guides.