Air Core Inductors — High-Frequency, High-Q, No Saturation

Air core inductors are wound coils that use air, or a non-magnetic former, as their core material instead of ferrite, iron or powdered metal. Because there is no magnetic core to saturate, the inductance stays constant regardless of current, core losses stay near zero, and the quality factor (Q) remains high across a very wide frequency range. ADD Components is a professional electronic components distributor supplying air core inductors from Coilcraft and other leading brands, together with custom-wound coils built to your exact turns, wire gauge and geometry. From RF matching and filtering circuits to wireless charging transmit and receive coils and high-frequency transformer windings, our team supports procurement engineers and contract manufacturers in selecting the right inductance, Q factor and current rating for each design.

Product Types

Air Core Inductors (No Magnetic Core)

An air core inductor is simply a coil of wire, typically wound on a self-supporting structure, a low-loss plastic or ceramic former, or formed as a planar spiral on a PCB. Removing the magnetic core eliminates hysteresis and eddy-current losses and removes the saturation limit that constrains ferrite and iron-powder inductors at high current. The result is an inductor whose value stays stable with temperature and current, making it ideal for circuits that must not drift. The trade-off is lower inductance per turn and a more open magnetic field, so air core parts are used where high Q and stability matter more than compact inductance density.

RF and High-Frequency Applications

Air core inductors excel in RF circuits because their Q factor remains high well into the hundreds of megahertz and beyond, where ferrite-core parts degrade rapidly. They are used in antenna matching networks, filters, oscillators, impedance-matching circuits and RF power amplifiers, where low loss and stable inductance translate directly into better sensitivity and efficiency. Coilcraft's air core families — including the 2929SQ, 2222SQ and 1812SMS surface-mount series and the Midi Spring and Mini Spring through-hole series — are the reference choices for RF designers, and ADD Components stocks and sources them in volume.

Wireless Charging and Resonant Coils

Wireless charging relies on resonant inductive coupling between transmit and receive coils operating from roughly 100 kHz (the Qi standard) to several megahertz. Air core and low-loss coil structures are preferred for these resonators because they avoid the saturation and heating that a magnetic core would introduce at the high AC currents involved. Our team sources and arranges custom-wound planar and litz-wire coils for Qi-compliant and proprietary wireless power systems, helping customers match coil inductance, coupling and Q to their driver and receiver ICs.

High-Frequency Transformers

Air core coils are also wound into high-frequency transformers and inductively coupled structures used in RF isolation, resonant power conversion and signal coupling. Without a core, the transformer avoids saturation and hysteresis loss, though coupling is lower than a gapped or core-based design. These windings appear in RF amplifiers, wireless power links and pulse applications where bandwidth and linearity outweigh the need for tight coupling.

Custom-Wound Air Core Inductors

When an off-the-shelf part cannot meet the required inductance, current, frequency or form factor, ADD Components arranges custom-wound air core inductors. Specify the number of turns, wire gauge, coil diameter, lead style (through-hole, SMD or flying leads) and tolerance, and we coordinate winding, testing and delivery. Custom coils are common for wireless charging, RFID antennas and specialised RF matching where the exact geometry is dictated by the board layout and enclosure.

Key Selection Parameters

• Inductance and Tolerance: Air core parts typically span a few nanohenries to a few microhenries; confirm the value and tolerance (±5% or tighter for critical RF).

• Q Factor and Self-Resonant Frequency (SRF): High Q and high SRF are the primary reasons to choose air core — verify both at your operating frequency.

• Current Rating: Without a core there is no saturation, so current is limited only by wire heating and DC resistance (DCR).

• DCR: Lower resistance reduces loss and heating in high-current resonant and charging circuits.

• Mounting Style: Surface-mount (square/flat air core) versus through-hole (spring and leaded) versus custom planar or litz-wound coils.

• Operating Frequency: Match the part's SRF and Q curve to the application, whether RF, resonant wireless power or pulse work.

• Form Factor and Layout: Air core parts radiate more field than shielded cores — consider spacing and nearby components in PCB layout.

Representative Inductors We Source

Send Us Your Inductor Requirements

ADD Components is a Hong Kong-based electronic components distributor supplying air core inductors, RF inductors and custom-wound coils to OEM, EMS and contract manufacturing customers worldwide. We source Coilcraft surface-mount and spring-style air core parts alongside Vishay wirewound RF inductors, and arrange custom-wound coils for wireless charging, RFID and RF matching. Send your part numbers, target values or coil drawings for a same-day quotation — we support spot buys, blanket orders and inductor wholesale programs.

Email: Info@addcomponents.hk | Tel: +852 5334 3091 | WhatsApp: +852 5334 3091

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