Application Cases

Experiment Name: Application of High-Voltage Power Amplifier in Testing Acoustic Resonance Electrically Small Antennas

Research Direction: Acoustic Resonance

Experimental Equipment:
ATA-2031 High-Voltage Amplifier, Signal Generator, Impedance Analyzer, Network Analyzer

Experimental Content:
Three different types of acoustic resonance electrically small antennas were designed, including:

1. Acoustic resonance electrically small antenna based on Fe-Si-B/PIMNT composite material.

2. Acoustic resonance electrically small antenna based on Fe-Ga/PIMNT composite material.

3. Thin-film acoustic resonance electrically small antenna based on Fe-Ga/AlN.

The study focuses on the design and implementation schemes of these different types of acoustic resonance electrically small antennas. By analyzing structural parameters, material parameters, and operating modes, the key parameters affecting the performance of the antennas are identified. Additionally, a corresponding testing system is designed.

Experimental Procedure:
A self-built system for measuring the magnetoelectric coupling coefficient of magnetoelectric composite materials was employed. The basic principle is as follows: a signal generator produces an AC signal applied to the modulation coil to generate an alternating magnetic field dH, which serves as the input signal for the sample. While the magnetoelectric composite material receives this alternating magnetic field, a DC scanning magnetic field H is applied. The magnitude of this scanning magnetic field is controlled by a DC power supply, with feedback from a Gauss meter to precisely control its size and variation. Finally, the alternating magnetic field signal dH from the modulation coil, the scanning magnetic field signal H, and the alternating voltage signal dE obtained from the magnetoelectric composite material are processed through components such as an oscilloscope and computer to derive the performance parameters of the magnetoelectric composite material. Due to the significant inductive reactance of the modulation coil at high frequencies, a power amplifier is typically connected between the signal generator and the modulation coil. The system mainly consists of three modules:

1. AC Magnetic Field Application Module

2. DC Magnetic Field Application and Detection Module

3. AC Signal Detection Module

The AC Magnetic Field Application Module is used to apply an AC input magnetic field with adjustable frequency and intensity to the magnetoelectric coupling device. A signal generator (arbitrary waveform function signal generator) is selected. This signal generator provides sinusoidal wave signals ranging from 1 μHz to 25 MHz, with a sampling rate of 200 MSa/s. To apply sufficient voltage/current to the modulation coil at high frequencies to obtain a uniform magnetic field of a certain strength, the signal generator of the magnetoelectric coupling measurement system is connected to a voltage amplifier. The ATA-2031 high-voltage amplifier produced by Xi'an Antai Electronics is selected, with an output voltage of 300 Vp-p (±150 Vp), an output current of 120 mA, and an output voltage gain of 0–50 times (0.1 step).

To apply a uniform magnetic field to a specific area of the sample while ensuring a magnetic field intensity of at least 1 Oe (design magnetic field frequency range: DC to 100 kHz), a specially designed small Helmholtz coil is used as the AC magnetic field generation coil. A brief introduction is as follows: to provide an AC magnetic field to the sample, a uniform cylindrical magnetic field region of φ20 mm × 50 mm is required at the center of the coil. A high-voltage amplifier with a large output voltage of 300 Vp-p (±150 Vp) and a large output current of 120 mA is selected. The impedance values of Helmholtz coils with different numbers of turns and sizes are calculated. By adjusting the number of turns and dimensions, the total impedance remains largely unchanged, but the size of the uniform magnetic field region obtainable under the excitation of this voltage amplifier is maximized.

Experimental Results:
In Maxwell simulations, only current excitation of the coil is considered, and the uniformity of the magnetic field is calculated under static magnetic field conditions. Analysis of the simulation results shows that a uniform magnetic field region of at least φ30 mm × 50 mm can be achieved (magnetic field uniformity: ±5%). The magnetic field distribution on the corresponding plane inside the coil is analyzed.

The DC Magnetic Field Application Module is mainly used to apply a controllable DC bias magnetic field to the magnetoelectric composite material. A self-made coil or a large Helmholtz coil is used, and a DC voltage (0–31 V) is directly applied to the coil using a DC source. A Gauss meter is used to calibrate the magnetic field-current constant. Calibration results indicate that the large Helmholtz coil can produce a DC magnetic field of 0–145 Gs.

The AC Signal Detection Module is used to detect the voltage signal generated by the sample. The intensity of the alternating magnetic field signal can be easily calculated using the output current of the voltage amplifier and the current-magnetic field constant of the calibrated coil.

Figure: Specifications of the ATA-2031 High-Voltage Amplifier