| The development and popularization of Electrosurgery products have provided convenience for many complex precision operations and minimally invasive operations.The electromagnetic knife system suitable for a variety of surgical scenarios has emerged at the historic moment.However,most of the electromagnetic knife systems on the market have some difficulties in stabilizing the power output,generally with the problem of uneven heating of the electric and magnetic knife,which will lead to tissue adhesion,high smoke and even thermal damage to surrounding tissues.In response to this status and practical needs,this paper mainly designs the RF and microwave components of an electromagnetic scalpel surgical system with controllable power,adjustable frequency,stable thermal effect,and high safety.The RF and microwave design revolves around its reconfigurable filter and several different functional electromagnetic scalpel heads.The main research content includes the following three parts:(1)The composition of the electromagnetic knife surgery system has been optimized.Based on the system circuit structure,a power control method for the electromagnetic knife surgery system has been designed,and its application scenarios have been analyzed for design requirements.When the electromagnetic knife is working,it needs electromagnetic energy to heat the knife head to evaporate the vaporized tissue.Therefore,the heat calculation method in the system is also designed to facilitate the calculation of the electric field intensity required by the electromagnetic knife to rapidly increase the temperature.In order to achieve a stable increase in blade temperature and prevent adhesion of tissues,some thermal storage phase change materials have been filled into the electromagnetic knife,which is expected to solve the problems of temperature instability,adhesive tissue,and high smoke that exist in most electromagnetic knife products on the market.(2)The main components of the electromagnetic scalpel surgical system,including reconfigurable filters and electromagnetic scalpel heads,were designed for radio frequency and microwave.A compact reconfigurable microstrip bandpass filter with a center frequency of1.35 GHz based on a T-shaped dual mode resonator has been designed.By changing the variable capacitance value loaded on the resonator,the center frequency of the filter can be adjusted.By optimizing the bending method of microstrip lines,the miniaturization of the filter was achieved,and the final dielectric substrate size was 31.17mm×16.94mm×0.4mm.The designed reconfigurable filter has a passband range of 1.23 GHz to 1.48 GHz and1.48 GHz to 1.75 GHz,with insertion loss less than 2d B and stopband suppression greater than 40 d B,indicating good selectivity.(3)Several electromagnetic knife heads with different functions have been designed,including cutting knife heads,radiating knife heads,and clamping knife heads,which are expected to achieve different functions such as heating and cutting tissue,evaporating and vaporizing tissue,cooling and coagulation,and clamping tissue,suitable for various surgical scenarios.The designed radiation cutting head has an electromagnetic radiation absorption efficiency of up to 98%,a return loss greater than 10 d B,and excellent directionality.The actual measurement results are close to the simulation results.A clamp type electromagnetic knife head was also designed,with an electromagnetic radiation absorption efficiency of up to 96%.By analyzing the distribution of electric field and specific absorption ratio(SAR)in the simulation results,the thermal effect generated by it was theoretically verified to comply with medical electromagnetic safety standards,and it is expected to ensure safety in practical applications. |
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