Growing Demand for Low-Frequency RFID and Smart Cards: How Can 125 kHz Air-Core Coils Ensure Reliable Reading?

125kHz low-frequency RFID technology continues to penetrate fields such as smart cards, access control systems, animal identification, and industrial tracking. Its strong signal penetration and low susceptibility to metal and liquid interference give it irreplaceable advantages in applications such as access cards, animal chips, and industrial pallet tracking. As smart cards and IoT devices become more widespread, demand for low-frequency RFID antenna coils is growing steadily, while core requirements are being placed on high Q factor, wide inductance range, miniaturisation and low profile, and reliable mechanical structures.

The SHINHOM 125kHz RFID Antenna Air Core Coil uses coreless honeycomb Litz wire winding and a multi-layer structure design. With an inductance of 3.8mH and a thickness of 4.5mm, it provides an antenna coil solution for stable reading in low-frequency RFID applications.

Trend 1: High Q Factor Ensures Read Range and Stability

Trend Requirements

• The read range of low-frequency RFID is directly related to the Q factor of the antenna coil

• The higher the Q factor, the better the coil's selectivity and signal strength

• Traditional winding methods have limitations in high-frequency loss and consistency

Suitability of Air Core Coils

• The coreless design eliminates core loss, helping to improve the Q factor

• Honeycomb Litz wire winding reduces high-frequency loss, further optimising the Q factor

• High Q factor and wide inductance range adapt to tag designs with different read range requirements

Trend 2: Wide Inductance Range Adapts to Different Tag Designs

Trend Requirements

• Different tags such as smart cards, access cards, and animal chips have different inductance requirements

• Differences in tag size and read range require flexible and adjustable coil parameters

• Standard products struggle to cover all application scenarios

Suitability of Air Core Coils

• Custom winding shapes and inductance values are supported to match different tag designs

• The standard parameter of 3.8mH ±10% can serve as a design baseline

• Inductance and resistance requirements can be matched according to customer inquiries

• The wide inductance range covers a variety of low-frequency RFID applications

Trend 3: Miniaturisation and Low Profile to Suit Card Thickness Constraints

Trend Requirements

• Smart cards and access cards typically have strict thickness limits (ISO standard approximately 0.76mm-0.84mm)

• Coils need to be as thin as possible while maintaining sufficient inductance and Q factor

• Multi-layer structures must achieve stable electrical performance within a limited thickness

Suitability of Air Core Coils

• Maximum coil thickness of 4.5mm, adapting to embedding requirements for cards and tags

• Inner diameter 31.8×10.8mm, outer diameter 36×15.5mm Max – compact dimensions

• 0.14mm wire diameter combined with honeycomb winding achieves 3.8mH inductance within limited space

• Multi-layer structure design balances low profile and electrical performance

Trend 4: Reliable Mechanical Structure for Mass Production

Trend Requirements

• Smart cards and tags require mass production, making coil consistency and reliability critical

• Coils must maintain structural stability during card lamination, bending, and daily use

• Windings need to be securely bonded to prevent deformation or open circuits

Suitability of Air Core Coils

• Windings are bonded with strong adhesive for a stable structure

• Multi-layer structure design enhances mechanical strength

• Bobbinless design reduces assembly steps, suitable for mass production

• Complies with ISO9001:2015 and ROHS certification requirements

Application Scenarios

Conclusion: Providing a Stable Antenna Coil Solution for Low-Frequency RFID Applications

The SHINHOM 125kHz RFID Antenna Air Core Coil enhances the Q factor through coreless honeycomb Litz wire winding, adapts to the low-profile requirements of cards and tags with 3.8mH inductance and 4.5mm thickness, and ensures mass-production reliability through a multi-layer structure and strong adhesive. It provides a stable antenna coil solution for low-frequency RFID applications such as smart cards, contactless payment, access control, IoT, logistics tracking, and identity recognition.

For selection recommendations or customised solutions based on your specific application (read range, card thickness, inductance requirements), please contact our technical team.