Application Cases

Research Direction：

Multilevel Circuit Modeling of Biological Tissues, Radio energy transmission,Asymmetric insulating layer coupler structure design.

Experimental objective：

Research was conducted on the electric field coupling radio energy transmission for implantable devices in the human body. An accurate circuit model was established for the multi-tissue layer environment of the human body. Further, the structure of the coupling device was designed. Experiments were carried out using the designed coupling device. The experimental results were compared with the simulation results and analytical calculation results to verify the accuracy of the circuit model and the energy transmission capability of the coupling device.

Testing equipment：

Signal generator,ATA-1220E Broadband power amplifier, High-voltage direct current power supply, Scope (electronic instrument), High-pressure differential probe,Impedance Analyzer,Thermal incubator,etc.

Experimental process：

During the experiment, a high-frequency AC power supply is required to provide electrical energy to the transmitting side. The power signal generator is connected to the ATA-1220E power amplifier to generate a 6.78 MHz sine voltage as the input power. The voltage and current on the transmitting side and the receiving side are measured using an oscilloscope to calculate power and efficiency. An experimental platform was set up using fresh pork as the energy transmission medium to conduct load variation experiments.

Figure1 Live photo of the experimental platform system.

Figure2 Diagram of the experimental system connection.

Experimental results：

Due to the differences in dielectric properties between pork tissue and human tissue, there are certain discrepancies between the experimental results, the COMSOL simulation results, and the numerical calculation results. However, within a certain error range, these results prove the accuracy of the proposed multi-layer tissue link model. Finally, 106.6mW was efficiently transmitted to the load with an efficiency of 45.28%, and this power level enables the cardiac pacemaker to operate for 30 days with wireless charging for one hour.

Figure3 . Experimental, simulation and analytical results of (a) PDL versus RLfor coupler with asymmetric insulation (t1=0.015 mm, t2=0.15 mm). (b) PDL versus RL for coupler with symmetric insulation (t1=0.015 mm, t2=0.015 mm)

Figure4 Waveforms of the asymmetric insulation coupler when RL=82 Ω.

The effectiveness of the amplifier in this experiment：

1.Provide a high-frequency sinusoidal driving power supply: The low-voltage signal output by the signal generator (Tektronix AFG3102C) is linearly amplified to a 6.1 Vp sinusoidal voltage (with a frequency of 6.78 MHz) as the input excitation source for the transmitting end (Tx), driving the compensation inductor and the emitter plate, thereby establishing an alternating electric field in the tissue and achieving capacitively coupled energy transmission.

2.Accurate measurement of the system power transmission efficiency (PTE): The output of the power amplifier provides a stable and low-distortion driving signal for the system, enabling the input voltage and input current to be accurately captured by the oscilloscope, thereby calculating the input power and output power, and ultimately obtaining the experimental value of PTE (for example, the PTE measured in the asymmetric structure experiment was 45.28%).

Application fields：

Subcutaneous medical sensor、Neural electrical stimulation and modulation equipment、Implantable drug delivery system、Wearable and Epidermal Electronic Devices