A multifunctional energy-saving magnetic field generator

Abstract

To improve the energy utilization of magnetic field generators for biological applications, a multifunctional energy-saving magnetic field generator (ESMFG) is presented. It is capable of producing both an alternating magnetic field (AMF) and a bipolar pulse magnetic field (BPMF) with high energy-saving and energy-reuse rates. Based on a theoretical analysis of an RLC second-order circuit, the energy-saving and energy-reuse rates of both types of magnetic fields can be calculated and are found to have acceptable values. The results of an experimental study using the proposed generator show that for the BPMF, the peak current reaches 130 A and the intensity reaches 70.3 mT. For the AMF, the intensity is 11.0 mT and the RMS current is 20 A. The energy-saving and energy-reuse rates for the AMF generator are 61.3% and 63.5%, respectively, while for the BPMF generator, the energy-saving rate is 33.6%. Thus, the proposed ESMFG has excellent potential for use in biomedical applications.

Comparative Study of Square and Circular Loop Frequency Selective Surfaces for Millimeter-Wave Imaging Diagnostics Systems

“…These electric charge densities are accumulated at the horizontal ( x -direction) strips of the loops, creating the capacitive part “ C .” Whereas, the magnetic field is induced around the vertical ( y -direction) strips of the loops due to the flow of electric current that forms of an inductive part “ L ” in the ECM. Further, an electromagnetic interaction occurs between the top and bottom FSSs separated by the thin substrate, creating the mutual induction “ M ” and series capacitance “ C s ” in the ECM [ 6 ].…”

“…Also, the proposed FSS filters exhibit insensitive response to the oblique incident angle of 14 degrees, which is adequate for the mm-wave imaging diagnostic system application at KSTAR in Daejeon, Korea. The oblique incident angular performance of the proposed FSS can be increased up to 40 degrees by decreasing the period p of unit cell or gap g between the adjacent elements [ 6 ]. In the implemented design, a trade-off between a high Q-factor and high oblique incident performance has been made.…”

“…When excited by an incident plane wave, the FSS resonates at a particular frequency or multiple frequencies depending on the properties of the periodic array structure, dimensions and dielectric substrate. The conventional FSSs are interpreted as capacitive or inductive structures or sometimes a combination of both [ 2 , 3 , 4 , 5 , 6 ].…”

“…Recently, the FSSs were implemented as notch, band-stop and high-pass filters for mm-wave imaging diagnostic systems [ 22 , 23 , 24 , 25 , 26 ]. In the studies, the resonant frequencies of the FSS-based filters were 105 GHz, 110 GHz, 140 GHz and 170 GHz for imaging diagnostic systems for tokamak plasmas [ 6 , 24 ]. In these systems, the FSS-based protection was essential to protect the receiver electronics from unwanted stray signals by providing high rejection of, often, powerful unwanted signals.…”

“…With small-sized FSS structures [ 27 , 28 , 29 ], high-precision fabrication technique can be applied without difficulty, but, as the size of the FSS panel becomes bigger, significant increase in fabrication cost can occur. In this regard, recently, our group has developed and reported a low-cost fabrication technique for large-size FSSs (~19.7 × 6.3 inches at 170 GHz) with high performance at mm-wave range to protect the mm-wave ECEI receiver [ 6 ]. In the study, an array of square loops on both sides of the substrate was used, but, with using the commercial PCB process, the resonant frequencies of the FSSs from multiple prototypes showed variations of around 3 GHz deviated from the designed values.…”