Application Cases

Experiment Name: Radiation Performance Test of Magnetoelectric Mechanical Antenna

Research Direction:
Design of symmetric magnetoelectric mechanical antenna, multiphysics coupling modeling, structural optimization, and radiation performance validation

Experiment Objective:
This experiment focuses on the experimental validation and performance optimization of magnetoelectric antennas. Through systematic experimental design, theoretical models and simulation results are verified, and their engineering applicability is evaluated. Based on a composite structure of PZT-5H piezoelectric material and Terfenol-D magnetostrictive material, the physical antenna prototype was fabricated, including copper electrode placement, epoxy resin bonding, and integration of a permanent magnet biasing device, ensuring stability and repeatability of experimental conditions. A complete testing system was established, and multiple sets of experiments (resonant frequency testing, bias magnetic field regulation, driving voltage response, directional analysis, distance attenuation law, inductor integration optimization, and complex environmental adaptability testing) were conducted to comprehensively investigate the radiation characteristics and transmission performance of the magnetoelectric antenna.

Testing Equipment:

1. Antenna Fabrication Equipment/Materials

• 3D printer (white photosensitive resin for fabricating antenna protective shell)

• Vacuum environment equipment (curing epoxy resin to avoid bubble formation affecting bonding)

• PZT-5H piezoelectric ceramic (135 mm × 20 mm × 5 mm)

• Terfenol-D magnetostrictive material (120 mm × 20 mm × 5 mm)

• NdFeB permanent magnet (20 mm × 20 mm × 10 mm, providing bias magnetic field)

• Epoxy resin AB adhesive (bonding functional layers)

• Copper foil (fabricating electrodes)

• Silver (Ag) electrode layer (pretreatment of piezoelectric material)

• Functional Materials:

• Processing Equipment:

2. Transmitter Equipment

• Aigtek ATA-2022H dual-channel high-voltage amplifier (gain: 0–60× adjustable; maximum output voltage: 200 Vp-p; maximum output current: 500 mA (>50 Hz); used to amplify low-amplitude signals from the signal source)

• Tektronix AFG1062 dual-channel arbitrary waveform function signal generator (bandwidth: 60 MHz; output: 1 μHz–60 MHz sine wave; supports sweep frequency/modulation functions)

• Signal Source:

• Amplifier:

3. Receiver Equipment

• VLF data acquisition system (includes analog signal conditioning, acquisition, calibration functions)

• Host computer

• Three-axis fluxgate magnetic sensor (sensitivity: 0.1 pT/Hz¹/² at 1 Hz, 0.01 pT/Hz¹/² at 100 Hz; conversion sensitivity: 100 mV/nT; detection bandwidth: 0.1 Hz–10 kHz; synchronously measures three-dimensional magnetic fields)

• Sensor:

• Data Acquisition:

  
  

Figure 1: Signal Generator and Power Amplifier Schematic

Experimental Procedure:

1. An experimental testing platform was established based on the radiation mechanism of the magnetoelectric mechanical antenna. The signal generator served as the excitation source, outputting a sinusoidal excitation signal matching the antenna's resonant frequency. This signal was amplified by the high-voltage amplifier and input into the piezoelectric material. Through the transition of the intermediate epoxy resin layer, vibrations were transmitted to the magnetized magnetostrictive layer, radiating magnetic field signals. The receiver employed a three-axis magnetic sensor, and the signal's frequency and intensity information were obtained after data storage and post-processing.

2. To better excite the piezoelectric material, adhesive-backed copper foil was attached to the upper and lower surfaces of the piezoelectric material. Epoxy resin adhesive, mixed in AB form, was evenly applied to the surfaces of the piezoelectric and magnetostrictive materials. After removing excess adhesive, the assembly was placed in a vacuum environment for 12 hours to fully cure. The bias magnetic field was provided by two NdFeB permanent magnet blocks (20 mm × 20 mm × 10 mm). The antenna structure is shown in Figure 2.

   
   

Figure 2: Antenna Structure Schematic

3. 3D printing technology was used to fabricate the antenna shell, composed of white photosensitive resin. Its structural diagram is shown in Figure 5.3. The permanent magnet device inside can slide to adjust the strength of the bias magnetic field. The fixed groove dimensions are 15 mm × 20 mm × 5 mm, matching the side dimensions of the antenna. Embedding the antenna into the groove provides fixation, ensuring the shell not only protects the antenna but also stabilizes experimental conditions, improving accuracy across multiple experiments and long-term result stability.

4. The function signal generator used was a dual-channel arbitrary waveform function signal generator (Tektronix AFG1062) with a bandwidth of 60 MHz, sine wave range of 1 μHz–60 MHz, sawtooth wave range of 1 μHz–2 MHz, pulse wave range of 1 mHz–30 MHz, sampling rate of 300 MS/s, and vertical resolution of 14 bits. Using the generator's continuous, modulation, and sweep functions, performance testing of the magnetoelectric mechanical antenna was conducted.

5. The reception system mainly included a three-component inductive magnetic field sensor, VLF data acquisition system, acquisition control software, and supporting equipment. The VLF data acquisition system handled key tasks such as analog signal conditioning, acquisition, calibration, and data storage. The host computer acquisition control software managed the VLF data acquisition system via WiFi, including network configuration, system status monitoring, parameter configuration, data acquisition control, and real-time curve viewing. The operating frequency bandwidth was 0.1 Hz–10 kHz, with sensitivities of 0.1 pT/Hz¹/² at 1 Hz and 0.01 pT/Hz¹/² at 100 Hz, and a flat conversion sensitivity of 100 mV/nT. The experimental block diagram is shown in Figure 3, and the actual setup photo is in Figure 4.

   
   

Figure 3: Block Diagram of Magnetoelectric Mechanical Antenna Radiation Performance Test

Figure 4: Actual Photo of Magnetoelectric Mechanical Antenna Radiation Performance Test

Experimental Results:

1. Resonant Frequency Test Results

• Fine scanning of the 5–6 kHz range revealed a magnetic induction intensity peak at 5.3406 kHz, highly consistent with COMSOL simulation results (5.34 kHz). Deviations were attributed to residual stress and stiffness changes after epoxy curing.

2. Bias Magnetic Field Test Results

• Magnetic induction intensity initially increased and then decreased with permanent magnet distance, peaking at 6 cm (optimal bias magnetic field strength). Beyond 6 cm, magnetostrictive layer magnetic domain saturation and increased losses led to reduced radiation intensity.

3. Driving Voltage Test Results

• Within the antenna's linear operating range (10 V–110 V), magnetic induction intensity was proportional to the excitation voltage, validating the theoretical model's assumption of "electric field-driven mechanical strain linear transfer."

4. Directional Test Results

• x-o-z plane (vertical plane): Radiation pattern was symmetric, with maximum magnetic induction intensity at 0° and 180° (antenna length direction) and minimum at 90° and 270°, consistent with magnetic dipole radiation mode.

• x-o-y plane (horizontal plane): Magnetic induction intensity was nearly uniform across angles, reflecting the isotropic nature of piezoelectric layer electric dipole radiation.

5. Distance and Radiation Intensity Test Results

• Magnetic induction intensity decayed as $r^{-3}$ with increasing distance (near-field theoretical law). At 60 m, magnetic induction intensity measured $3.31\times 10^{-14}\text{T}$, with an estimated intensity of $5\times 10^{-16}\text{T}$ at 120 m.

6. Inductor Impact Test Results

• 0.5 mH/0.9 mH: shifted to higher frequencies (+2 Hz)

• 1.0 mH/1.5 mH: shifted to lower frequencies (-1 Hz/-5 Hz)

• 0.5 mH: 1.83×

• 0.9 mH: 1.89×

• 1.5 mH: 2.56× (optimal inductance value)

• External inductors significantly enhanced radiation intensity:

• Resonant frequency shifts were observed:

• Bandwidths were narrower compared to the no-inductor group.

7. Complex Electromagnetic Environment Test Results

• Third floor: $2.77\times 10^{-12}\text{T}$ (≈20% attenuation)

• Second floor: $2.19\times 10^{-12}\text{T}$

• First floor: $1.97\times 10^{-12}\text{T}$

• After penetrating three layers of concrete:

• Attenuation primarily resulted from concrete absorption and signal reflection, validating the antenna's strong low-frequency penetration capability and interference resistance.

Recommended Power Amplifier: ATA-2022B

Figure: ATA-2022B High-Voltage Amplifier Specifications

This document is compiled and published by Aigtek. For more case studies and detailed product information, please continue to follow us. Xi'an Aigtek has become a large-scale instrument and equipment supplier in the industry with an extensive product line. All demo units are available for free trial.