MUT Circuit Electrically Controls Membrane Bandwidth
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Solution Overview
Problem
Micromachined ultrasonic transducers (MUTs) lack sufficient bandwidth for airborne applications, which require a larger bandwidth compared to their performance in contact or near-contact body imaging applications.
Innovation Solution
The MUT circuit electrically controls the membrane's movement to transmit ultrasonic waves, allowing for the generation of ultrasonic waves with multiple cycles of equal amplitude, maximizing energy transmission in the shortest time and enabling the circuit to stop the wave quickly, thereby increasing the system's bandwidth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the membrane is allowed to vibrate freely at its natural mechanical resonant frequency, then the MUT can generate ultrasonic waves effectively, but the mechanical oscillation persists for a long time due to physical dampening, limiting the bandwidth
Solution Approach 1:
The patent applies preliminary anti-action by introducing a cancellation voltage waveform that generates a counteracting force on the membrane before the natural mechanical oscillation can fully decay. This cancellation waveform is specifically designed to oppose and terminate the membrane's vibration, effectively stopping the ultrasonic wave generation in a controlled manner rather than allowing it to decay naturally over time.
Solution Approach 2:
The patent employs periodic action by using a multi-cycle voltage waveform consisting of an initial voltage waveform followed by a cancellation voltage waveform. This periodic structure allows the membrane to be driven for a specific number of cycles to generate the desired ultrasonic energy, then immediately terminated by the cancellation phase, enabling precise control over the duration of membrane vibration and thus expanding bandwidth.
2Productivity
If the MUT circuit uses traditional pulse generation, then the membrane vibrates at its natural resonant frequency, but the amplitude decays over time due to physical dampening, requiring longer pulses and reducing bandwidth
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing the optimal multi-cycle voltage waveform in memory, including both the initial excitation phase and the cancellation phase. This preliminary preparation allows the system to execute the complete waveform sequence without real-time computation delays, maximizing energy transmission efficiency while minimizing the actual pulse duration applied to the membrane.
Solution Approach 2:
The patent implements feedback by using a controller that coordinates the sequence of voltage waveforms based on the desired ultrasonic output requirements. The controller monitors the transmission needs and selects appropriate waveforms from memory, adjusting the timing and characteristics of the voltage pulses to optimize energy transfer while maintaining precise control over pulse duration and bandwidth.
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 bandwidth of the MUT circuit, allowing for efficient transmission and reception of ultrasonic waves, particularly in airborne applications by reducing mechanical oscillation and enabling shorter transmit pulses.
Implementation Method 1
The voltage pulse VP, in turn, causes MUT membrane 112 to vibrate at the natural mechanical resonant frequency of MUT 110, and thereby generate an ultrasonic wave UW at that frequency.
Implementation Method 2
Two common types of MUTs are a capacitive MUT (CMUT), and a piezoelectric MUT (PMUT).
Data Source
AI summary
A micromachined ultrasonic transducer (MUT) circuit, which has a MUT with a MUT membrane that can vibrate back and forth to transmit an ultrasonic wave, electrically controls the movement of the MUT membrane by controllably transferring energy to the MUT membrane, thereby allowing the MUT membrane to transmit substantially any desired ultrasonic wave.