Kinghelm RF Filter KH-SAWF244A: A SAW Bandpass Filter Enhancing Bluetooth and Wi-Fi Link Stability

The rapid rise of smart wearable devices, TWS earbuds, wireless modules, and IoT applications has made the 2.4GHz ISM band one of the busiest wireless communication frequencies in the world. With the increasing number of Bluetooth and Wi-Fi devices operating simultaneously, signal congestion and interference have become major concerns for engineers. To ensure stable wireless links, low-loss and high-selectivity RF filters have become essential components in modern wireless designs.

Kinghelm’s KH-SAWF244A RF Surface Acoustic Wave (SAW) Bandpass Filter is designed precisely for these challenges—enhancing the stability, purity, and reliability of Bluetooth and Wi-Fi communications in complex multi-protocol environments.

Kinghelm KH-SAWF244A Product Image

Why SAW Filters Matter in 2.4GHz Wireless Communications

The 2.4GHz ISM band is widely used by multiple wireless standards, including:

• Bluetooth Classic and BLE

• Wi-Fi 802.11b/g/n

• Zigbee

• Thread

• Various proprietary 2.4GHz wireless systems

With so many wireless systems overlapping in the same frequency band, interference is inevitable. This makes SAW filters (Surface Acoustic Wave filters) crucial for ensuring clean RF signals by selectively allowing desired frequencies to pass while suppressing unwanted interference from neighboring bands.

SAW filters are valued for their high frequency selectivity, temperature stability, reliability, and consistent performance—making them indispensable in Bluetooth headsets, wearables, wireless modules, and IoT devices.

Core Performance Features of the KH-SAWF244A

Kinghelm KH-SAWF244A is a 2.4GHz SAW bandpass filter with a center frequency of 2.442GHz, covering the main operating ranges of Bluetooth and Wi-Fi devices. Its key characteristics include:

1. Low insertion Loss (1.8dB typical) – Better Signal Integrity

Low insertion loss means minimal signal attenuation, resulting in:

• Higher receiver sensitivity

• More stable wireless links

• Improved signal range and reliability

This is especially critical for TWS earbuds, Wi-Fi modules, and IoT devices operating in interference-heavy environments.

2. Wide Usable Bandwidth: 78MHz

With an effective bandwidth of 78MHz, the KH-SAWF244A can support:

• Bluetooth (BT/BLE)

• Wi-Fi 2.4GHz

• Multi-protocol systems

This ensures strong compatibility with dual-mode Bluetooth + Wi-Fi devices.

3. Low Ripple (1.2dB) for Smooth RF Transmission

Low passband ripple means a more uniform signal response, which:

• Reduces packet errors

• Ensures smooth data throughput

• Enhances overall connection quality

4. Strong Out-of-Band Rejection – Excellent Anti-Interference Performance

The filter effectively suppresses interference from nearby LTE bands (such as Band 7/40), making it ideal for devices requiring multi-radio coexistence.

5. Ultra-Compact SMD-5P Package (1.4 × 1.1 mm)

The miniature package allows easy integration into:

• TWS earbuds

• Smartwatches

• Compact Wi-Fi modules

• Miniaturized IoT terminals

This helps manufacturers achieve smaller, lighter, and more efficient product designs.

6. 50Ω Input/Output Impedance

Ensures seamless integration with mainstream RF front ends and wireless ICs.

Typical Application Scenarios

1. Bluetooth Audio Devices (TWS, Bluetooth Speakers, Voice Assistants)

TWS designs are highly size-constrained and often suffer from RF interference. The KH-SAWF244A helps:

• Reduce audio dropouts

• Improve stability between left and right earbuds

• Ensure more reliable Bluetooth connections

2. Wi-Fi Modules and Smart Home Devices

For products such as smart plugs, Wi-Fi bulbs, routers, and IoT hubs, stable connectivity is crucial.
The KH-SAWF244A improves:

• Network stability

• RF sensitivity

• Transmission consistency

3. Multi-Protocol Coexistence Devices (Bluetooth + Wi-Fi + LTE)

Many modern terminals integrate multiple wireless chips.
This filter helps mitigate internal RF conflicts by:

• Enhancing coexistence performance

• Reducing near-band interference

• Ensuring cleaner signal paths

4. Industrial IoT Systems

Industrial settings typically require higher RF robustness.
KH-SAWF244A provides reliable communication performance even in noisy environments.

Why Choose Kinghelm SAW Filters?

1. Proven RF Expertise

Kinghelm, a leading provider of antennas, RF components, and connectivity solutions, brings strong engineering know-how and high-quality production capabilities.

2. Strict Quality Control & Consistent Mass Production

SAW filters demand tight process control to ensure uniform performance.
KH-SAWF244A delivers consistent quality suitable for mass production.

3. Compact Size & High Reliability

Designed for highly integrated consumer electronics and IoT devices.

4. Environmentally Compliant

The product fully meets RoHS environmental standards, making it ready for global markets.

Performance Benefits for End Products

Using KH-SAWF244A in your wireless design provides clear advantages:

• Improves wireless link stability

• Enhances anti-interference performance in congested environments

• Boosts RF sensitivity and signal quality

• Helps products pass RF compliance tests more easily

• Saves PCB space due to its miniature package

• Optimizes multi-radio coexistence (Bluetooth + Wi-Fi + LTE)

All of these improvements lead to better user experience, fewer connection drops, and more stable product performance.

Kinghelm KH-SAWF244A Specification

Conclusion

Kinghelm KH-SAWF244A is a high-performance 2.4GHz SAW bandpass RF filter tailored for modern Bluetooth and Wi-Fi systems. Featuring low insertion loss, wide bandwidth, strong suppression, and an ultra-compact package, it meets the demanding requirements of consumer electronics, smart home devices, wearables, and IoT terminals.

If your wireless design requires stable, interference-resistant, and reliable 2.4GHz performance, the KH-SAWF244A is a dependable and cost-effective choice that will significantly enhance overall system quality.

About Kinghelm

Shenzhen Kinghelm Electronics Co., Ltd.（www.kinghelm.net）has technical backbones from Tsinghua University and UESTC, and has introduced overseas returnee professionals. Kinghelm is able to develop highly reliable and high-performance antenna and connector products.KH series products of "Kinghelm" brand include Beidou/GPS antennas, RF adapter connectors, plug connector, electrical data connectors, terminals, and customized vehicle harnesses, industrial / medical connectors, and special antenna connectors."Kinghelm connects world", Kinghelm has grown with the development of China's Beidou industry. Starting from supplying Beidou/GPS dual mode antennas, IPEX terminals, and RF adapter cables for automotive manufacturers, Kinghelm has continuously developed products. Currently, it has a series of WiFi, Bluetooth, NB-loT, LoRa, Zigbee, UWB, and GSM antennas, RFID tags, RF adapter cables, standard microwave antennas, vehicle grade SMA, SMB, FAKRA holders, coaxial cables, and can customize non-standard antenna connectors based on customer drawings or samples.