Time-Modulated Small Antenna for Bandwidth-Efficiency Tradeoff
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Solution Overview
Problem
Existing electrically small antennas face limitations in quality factors, bandwidths, and efficiencies, making them unsuitable for many communications and sensing applications.
Innovation Solution
The use of parametric time-modulated electrically small antennas with sectors operating in radiative and non-radiative modes, coupled by time-varying reactive components, allows for increased bandwidth and efficiency through spatially-discrete traveling-wave modulation, inhibiting harmonic radiation and maintaining high quality factors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the antenna size is reduced to be electrically small, then the antenna can be used in compact applications, but the quality factor, bandwidth, and efficiency deteriorate
Solution Approach 1:
The patent applies time-varying reactive components (such as time-varying capacitors or inductors) to the antenna structure, making the antenna parameters dynamic rather than static. This temporal modulation allows the antenna to overcome the conventional size-performance limits by creating effective coupling between different resonant modes, thereby improving quality factor and bandwidth while maintaining electrically small dimensions
Solution Approach 2:
The patent changes the reactive parameters of the antenna components over time through parametric modulation. By varying the reactance values dynamically at specific modulation frequencies, the antenna achieves enhanced coupling between radiative and non-radiative modes, which improves the efficiency-bandwidth product and overcomes the fundamental limitations of electrically small antennas
2Reliability
If time-varying reactive components are added to enhance bandwidth and efficiency, then the efficiency-bandwidth product improves, but the device complexity increases
Solution Approach 1:
The patent employs periodic modulation of the reactive components at specific frequencies to achieve mode coupling. This periodic action is implemented through time-varying capacitors or inductors that are modulated at frequencies corresponding to the difference between resonant modes, enabling enhanced bandwidth and efficiency while maintaining a relatively simple antenna geometry
Solution Approach 2:
The patent utilizes parametric modulation where the reactance values are varied periodically in time. This approach achieves complex electromagnetic behavior through controlled parameter changes rather than through complex physical structures, thereby improving the efficiency-bandwidth product with minimal increase in device complexity
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
This approach enhances the efficiency-bandwidth product of electrically small antennas by up to 4.4 times compared to conventional antennas, suppressing spurious harmonics and maintaining effective impedance matching over a broader bandwidth.
Implementation Method 1
at least one time-varying reactive component having a parametric modulation frequency configured to at least partially couple the resonance of the radiative mode to the resonance of the non-radiative mode at a negative frequency
Implementation Method 2
couple the resonance of the radiative mode to the resonance of the non-radiative mode
Implementation Method 3
a wave number in a radiating medium multiplied by a radius of a smallest sphere enclosing the electrically small antenna is less than 0.5
Data Source
AI summary
An example antenna assembly includes an electrically small antenna having at least two sectors, wherein the at least two sectors are coupled to operate in at least a first mode and a second mode, the first mode is a radiative mode having a resonance, and the second mode is a non-radiative mode. The antenna assembly includes at least one time-varying reactive component having a parametric modulation frequency configured to at least partially couple the resonance of the radiative mode to the resonance of the non-radiative mode at a negative frequency, wherein the parametric modulation frequency of the at least one time-varying reactive component is greater than or less than a frequency value which exactly couples the resonance of the radiative mode to the negative frequency of the non-radiative mode.