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Comprehensive Guide to RF Helical Bandpass Filters for Modern Communication

RF Filter Helical Filter Bandpass Filter 5G Communication Equipment Custom RF Components Microwave Filter Tunable Filter Wireless Communication Signal Processing
Table of Contents

Understanding RF Helical Bandpass Filters in Communication Systems
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RF Helical Bandpass Filters are passive components designed with multiple resonators, typically ranging from 2 to 6 sections. Their structure resembles a spiral coil, often referred to as a spiral filter. The core of a helical filter is a spiral coil encased in a square conductive shield. One end of the coil connects to the load, while the other remains open. This design operates similarly to a coaxial resonator, but the spiral shape shortens the effective wavelength, as the inner conductor reduces wave propagation speed. The wire length is only a quarter of the target wavelength.

These filters are known for their robust environmental adaptability. Standard operating temperatures range from -30°C to +75°C, with options for performance adjustments to suit environments as extreme as -40°C or +85°C. Thanks to their specialized manufacturing, helical filters achieve high Q values, resulting in excellent insertion loss and attenuation characteristics.

Helical Bandpass Filters are suitable for frequencies between 50 MHz and 3000 MHz. Their flexible design allows for quick structural adjustments to meet various frequency and bandwidth requirements. By increasing the number of resonators, the filter’s performance can be enhanced, with current designs supporting up to 6 resonators and achieving isolation levels above 80-90 dBc.

A notable feature is the ability to tune the center frequency. Users and engineers can fine-tune the center frequency by small increments (typically 1-3 MHz or 5-10 MHz), depending on the filter’s design parameters. This self-tuning capability enables users to select a filter with a center frequency close to their needs and then make precise adjustments after installation, optimizing output performance. As a result, these are often referred to as Helical Tunable Band Pass Filters.

Typical Applications
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Helical Bandpass Filters are widely used in:

  • Wireless communication equipment (e.g., truck, train, marine, and aviation communication)
  • Broadcasting equipment (TV, cable TV)
  • Network communication devices (indoor TX/RX, walkie-talkies)
  • Disaster prevention communication (firefighting, emergency broadcast)
  • Equipment measurement (laboratory development, testing centers)
  • Signal jamming (buildings, hospitals, military facilities)

7H Series RF Bandpass Temwell Helical Filters

Design Parameter Range
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Temwell offers extensive expertise in designing and manufacturing RF 5G BandPass Filters, with over 25 years of experience. The company provides a wide range of standard and custom helical bandpass filters, ensuring no performance loss when adjusting center frequency, bandwidth, attenuation, size, impedance, or connector type. Key design parameters include:

  • Center Frequency Range: 42 ~ 2600 MHz
  • Bandwidth Range: 5 ~ 200 MHz
  • Impedance: 50 ohm & 75 ohm
  • Attenuation: 10 dB increase per added pole
  • Size Options: 7H, 7S, 5R, 5W

For custom requirements, Temwell welcomes inquiries for tailored RF 5G bandpass filters. Contact Temwell for more information.

Series Overview
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Temwell 7H Series
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  • Center Frequency: 42 ~ 1500 MHz
  • Bandwidth: 5 ~ 120 MHz
  • Impedance: 50 ohm & 75 ohm
  • Attenuation: 10 dB per added pole

Temwell 7S Series
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  • Center Frequency: 196 ~ 1500 MHz
  • Bandwidth: 5 ~ 120 MHz
  • Impedance: 50 ohm & 75 ohm
  • Attenuation: 10 dB per added pole

Temwell 5W Series
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  • Center Frequency: 230 ~ 2600 MHz
  • Bandwidth: 5 ~ 120 MHz
  • Impedance: 50 ohm & 75 ohm
  • Attenuation: 10 dB per added pole

Temwell 5R Series
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  • Center Frequency: 200 ~ 2600 MHz
  • Bandwidth: 5 ~ 120 MHz
  • Impedance: 50 ohm & 75 ohm
  • Attenuation: 10 dB per added pole

Standard Catalog Overview
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A wide selection of standard helical bandpass filter series is available, each with detailed catalogs for both 50 ohm and 75 ohm impedance options. Explore the full range of series, including:

Featured Application Scenarios #

Trunking Radio System
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Temwell Group provides professional design services for trunking radio systems, including Project 25, TETRA, TETRAPOL, and DMR architectures, offering comprehensive RF microwave filter solutions. Learn more.

Drone & UAV System
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Temwell supports the evolving needs of 5G drone and UAV systems, offering custom filter designs and RF components. See more.

Radar
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Temwell’s R&D team delivers high-performance LNA and RF filters for radar projects, with custom proposals available in 7 days. Contact for details.

AloT Module Design
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Temwell offers effective RF filters and microwave components for all types of 5G AloT module designs, with rapid turnaround for custom solutions. Learn more.

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