MEDICAL ELECTRONICS Highly reliable electronic components


drive medical innovations Designing the next generation of wireless wearables, implantables and real-time external or in-body monitoring devices is a complex challenge that requires highly reliable electronic components that greatly exceed the performance of standard commercial alternatives.


To produce clean, reliable images, MRI systems rely on passive electronic components that must function in extremely strong magnetic fields and high- frequency RF conditions.


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eeting this objective requires passive electronic components that are precisely engineered to maintain accuracy and stability under demanding conditions. These components support essential functions such as reliable wireless communication, high resolution imaging and consistent data transmission.


This includes capacitors, inductors, chip antennas, baluns, RF and EMI filters, and RF matching networks that are pre-matched to popular medical wireless chipsets to simplify layout design and reduce component count, as well as band pass, high pass and low pass filters, and high Q capacitors and RF inductors.


High Q capacitors


One example of this is found in Magnetic Resonance Imaging (MRI) systems. To produce clean, reliable images, these systems rely on a wide range of passive electronic components that must function in extremely strong magnetic fields and high-frequency RF conditions. These passive elements must be non-magnetic, thermally stable and engineered to withstand high voltages as well as rapid current transients.


Capacitors, specifically, must demonstrate outstanding reliability because they directly affect the safety, precision and stability of both the imaging process and the high-power


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subsystems within the equipment. Even slight electrical variations can compromise safety, distort images, or cause system malfunctions. To ensure long term reliability, capacitors must tolerate substantial dielectric stress, repeated cycles of charging and discharging and sustained operation at elevated temperatures without performance degradation.


To meet these requirements in high-power RF sections such as coils, power supplies and amplifiers, designers frequently use high-Q capacitors.


For many high-power RF applications, the “Q factor” of embedded capacitors is one of the most important characteristics in the design of circuits. In theory, a “perfect” capacitor would exhibit no loss and discharge a full energy transfer, but capacitors always exhibit some finite amount of loss. The Q factor represents the efficiency of the capacitor in terms of its rate of energy loss.


This factor is important because the higher the energy loss, the more heat is generated within the capacitor that must be dissipated or cooled. In high power applications, the heat can be substantial and if the temperature rises significantly, it can damage nearby components.


High-Q capacitors are characterised as having ultra-low equivalent series resistance


JULY/AUGUST 2026 | ELECTRONICS FOR ENGINEERS


(ESR). In addition to minimising energy loss, High Q capacitors reduce thermal noise caused by ESR to assist in maintaining desired signal-to-noise ratios.


To achieve the lowest losses, certified suppliers such as Johanson Technology of Camarillo, Calif. utilise the lowest loss dielectrics, inks and electrode options in their high-Q designs. For more than 60 Years, the company has designed and manufactured multi-layer ceramic capacitors, EMI filters and other critical components for high reliability applications.


An example is the use of silver and copper electrodes, which outperform nickel in most high-Q applications. Nickel, which is commonly used in the lowest cost capacitors, is a poor conductor known for high loss at RF and microwave frequencies. Unlike silver and copper, nickel also creates a magnetic field that can interfere with devices such as MRI receiver coils.


Historically, Johanson Technology incorporates silver electrodes in its ultra- High Q (lowest ESR loss) offering, the E-Series multilayer RF capacitors in their high-power capacitors.


Preserving wireless connectivity High reliability electronics devices also play a key role in wireless connectivity for


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