Time Variant Antenna Modulating Resonance Frequency for Wideband Signals
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Solution Overview
Problem
Small antennas face challenges in achieving wideband signal transmission due to the fundamental physical limit that contradicts their size, limiting their bandwidth and making it difficult to transmit high data rates, particularly in applications like biomedical implants where space is constrained.
Innovation Solution
A circuit and method that modulate the resonance frequency of an electrically small antenna between two frequencies using a tuning circuit, powered by a periodic electrical signal, allowing the antenna to transmit wideband signals while maintaining a small size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the antenna size is reduced, then the device volume is minimized, but the bandwidth is narrowed
Solution Approach 1:
The patent applies dynamics by making the antenna's resonant frequency time-variant through periodic modulation. The antenna impedance is dynamically adjusted by varying the loading capacitance at a rate higher than the modulated signal frequency, enabling a small antenna to transmit wideband signals by exploiting transient states during frequency transitions.
Solution Approach 2:
The patent changes the parameter of resonant frequency over time by periodically modulating the loading capacitance. This parameter change allows the antenna to operate at different frequency points sequentially, effectively broadening the bandwidth beyond what a static small antenna could achieve.
2Productivity
If the antenna bandwidth is increased to transmit high data rates, then the data transmission rate is improved, but the antenna size must be increased
Solution Approach 1:
The patent uses dynamic frequency modulation where the antenna resonant frequency is varied periodically at a rate exceeding the modulated signal frequency. This dynamic operation allows high data rate transmission by utilizing the transient response of the antenna during frequency transitions, eliminating the need for a large physical bandwidth.
Solution Approach 2:
The patent implements periodic action by modulating the loading capacitance at a frequency higher than the modulated signal frequency. This periodic variation creates transient states that enable wideband signal transmission from a small antenna, allowing high data rates without increasing antenna volume.
3Volume of moving object
If a high-Q antenna is used to maintain small size, then the antenna volume is minimized, but the bandwidth is strictly limited by the Q factor
Solution Approach 1:
The patent overcomes the Q factor limitation by dynamically modulating the antenna resonant frequency. By varying the loading capacitance periodically at a rate higher than the modulated signal frequency, the antenna exploits transient states during frequency transitions to achieve wideband transmission, effectively decoupling bandwidth from the Q factor constraint.
Solution Approach 2:
The patent changes the resonant frequency parameter over time through periodic modulation of the loading capacitance. This time-variant operation allows a high-Q small antenna to transmit wideband signals by sequentially operating at different frequency points, bypassing the traditional bandwidth-Q factor tradeoff.
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
Enables the transmission of wideband signals with high data rates using a small antenna, effectively decoupling data rate from antenna bandwidth, suitable for applications like biomedical implants where space is limited.
Implementation Method 1
a tuning circuit configured for modulating a resonance frequency of the antenna between a first resonant frequency and a second resonant frequency
Data Source
AI summary
A circuit for tuning a resonance frequency of an electrically small antenna. The circuit includes a first source configured for providing a modulation signal, a second source configured for providing a periodic electrical signal, an antenna, and a tuning circuit configured for modulating a resonance frequency of the antenna in response to the modulation signal. The tuning circuit includes first and second capacitors that are alternately coupled to the antenna to change the resonance frequency of the antenna. The capacitor currently coupled to the antenna is decoupled from the antenna and the other capacitor is coupled to the antenna when the voltage across the capacitor currently coupled to the antenna is momentarily zero. In an exemplary embodiment, the tuning circuit comprises first and second inductors rather than capacitors. The inductors are switched into and out of the circuit when the current through the currently coupled inductor is momentarily zero.