Electrically Small Antenna Modulation for Wideband Transmission
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Solution Overview
Problem
Electrically small antennas are limited by their narrow bandwidth, restricting the rate of information transmission due to their high quality factor, which is tied to their electrical size, making it difficult to radiate high data rate signals effectively.
Innovation Solution
The antenna structure is modulated by changing the voltage across capacitors faster than the quality factor dictates, allowing for tunability in frequency, phase, and magnitude of the transfer function, enabling the transmission of wideband high data rate signals by pumping or damping charges, thereby overcoming the fundamental limits of small antenna designs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the antenna size is reduced to make it electrically small, then the antenna becomes more compact and easier to integrate, but the bandwidth becomes narrow and data transmission rate is limited
Solution Approach 1:
The patent applies dynamics by making the antenna structure time-varying through modulation. The antenna impedance is dynamically changed over time according to the data signal, allowing the electrically small antenna to transmit wideband signals by continuously adapting its electrical characteristics rather than being fixed at a single resonant frequency.
Solution Approach 2:
The patent changes the electrical parameters of the antenna by modulating its impedance. By varying the antenna impedance in accordance with the data signal, the system overcomes the narrow bandwidth limitation of electrically small antennas and enables high data rate transmission through parameter modulation rather than through increasing antenna size.
2Reliability
If the quality factor of the antenna is increased to improve resonance, then the antenna becomes more efficient at its resonant frequency, but the bandwidth decreases and fast signal variation is not permitted
Solution Approach 1:
The patent resolves this contradiction by making the antenna system dynamic. Instead of operating at a fixed high-Q resonance, the antenna impedance is modulated over time, allowing the system to maintain resonance efficiency while enabling fast signal variations through time-varying operation. The modulation frequency is kept much lower than the resonant frequency to maintain efficiency while allowing rapid data transmission.
Solution Approach 2:
The patent employs periodic modulation of the antenna impedance at a frequency much lower than the resonant frequency. This periodic action allows the antenna to operate efficiently at resonance while the slow modulation envelope carries the high-rate data signal, effectively separating the resonance function from the information transmission function.
3Stability of the object's composition
If the antenna operates as a leaky RLC resonator with fixed parameters, then the antenna structure is simple and stable, but the bandwidth is limited by the quality factor and cannot transmit wideband signals
Solution Approach 1:
The patent transforms the fixed-parameter resonator into a dynamic system by modulating the antenna impedance. The LTI (linear time-invariant) resonator becomes a time-varying system where the impedance changes according to the data signal, enabling the antenna to adapt its bandwidth and frequency response dynamically while maintaining the underlying resonator structure for stability.
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 allows for the transmission of high data rate signals through electrically small antennas, significantly expanding their bandwidth and data transmission capabilities beyond theoretical limits, enabling the use of small antennas for wideband communication.
Implementation Method 1
the voltage across the capacitor may be changed faster than the rate dictated by the quality factor of the resonator by pumping or damping charges from at least one capacitor to realize an arbitrary waveform
Implementation Method 2
a small antenna is also considered to be a leaky LC resonator which means that the antenna behavior is severely affected by its resonance nature
Data Source
AI summary
The present invention provides methods and devices to radiate wideband signals. The devices may include a tunable high Q narrowband antenna having a plurality of ports including a feed port and a tuning port as well as a tuning element coupled to the tuning port of the antenna. One or more voltage sources supply energy for radiating a radio frequency signal. A modulating signal generator may also be provided for generating a high data rate signal coupled at the tuning element for modulating the tuning element.