Low Pass Filter, DC~4.4GHz, Stopband Attenuation 30dB

In RF systems, the function of a low pass filter is to allow useful signals below the cutoff frequency to pass through smoothly, while significantly attenuating interference signals above that frequency. This filter has a cutoff frequency of 4.4GHz and a passband covering a wide frequency range from DC to 4.4GHz. Within the stopband, it can achieve a 30dB attenuation of high-frequency stray signals, effectively suppressing out of band interference to less than one thousandth of the original power, thereby ensuring that the backend circuit is not contaminated by harmonics and stray signals.

Features:

1. Both wide passband and high suppression system are available: The product's passband covers DC to 4.4GHz, which can meet the wideband signal transmission needs from baseband to microwave frequency band; Meanwhile, the attenuation capability of 30dB in the stopband ensures effective isolation against out of band interference. The implementation of this performance benefits from a reasonable filter order and topology design.
2. Standard SMA interface for easy system integration: The product adopts SMA type RF coaxial connector, which is one of the most universal interface standards in the microwave frequency band. It can easily connect with various testing instruments, transceiver modules, and antenna front ends, reducing the complexity of system integration.
3. Coaxial structure design, stable and reliable performance: Based on the coaxial transmission line structure design, this filter has good shielding and impedance consistency, and can maintain stable filtering characteristics in a wide frequency band, suitable for RF front-end scenarios with strict signal quality requirements.

Applications:

1. Harmonic suppression of transmitter: In wireless communication transmitters, this filter can be placed after the power amplifier to effectively filter out high-order harmonics generated by the amplifier, ensuring that the transmitted signal meets the compliance requirements of the spectrum transmission template and avoiding interference with adjacent channels.
2. Receiver anti-interference protection: At the front end of the receiver, this filter can be used to prevent strong out of band signals from causing low noise amplifier (LNA) saturation or mixer intermodulation distortion, improving the dynamic range and anti blocking ability of the receiving system.
3. Testing and measurement system: In RF testing instruments, this filter can be used as a pre filtering unit for signal sources or spectrum analyzers to purify test signals, eliminate high-frequency parasitic components at the DAC output, and improve measurement accuracy.
4. Radar and microwave systems: In the radar front-end and various microwave systems, this filter can be used to suppress the second harmonic of frequency bands such as the C-band (4.4~6GHz), protecting the back-end sensitive circuit from strong interference signals.

Qualwave supplies high stopband rejection low pass filters in frequency range DC~50GHz. The low pass filters are widely used in many applications. This article introduces a low pass filter with a DC to 4.4GHz frequency range and a stopband attenuation of 30dB.