High frequency design and EMR

Nuclear magnetic resonance (NMR) is a form of radio frequency (RF) spectroscopy. Its current popularity in applications, such as analytical chemistry and biomedical imaging was made possible by advances in RF design. Those advances permitted modern pulsed excitation and data acquisition in the microsecond time domain. Electron magnetic resonance (EMR) is equally powerful. But, its timescale for the spin dynamics (subnanosecond) and excitation spectrum (microwave) have posed formidable technological problems. These problems have forced the method to lag behind NMR. The situation is changing rapidly, however. Improvements in high frequency design now allow EMR to sit at an evolutionary threshold. These improvements and various technological solutions are considered. The processes involved in EMR are also discussed.