Helical Filters

Product Features

• High Q-factor: Helical resonators inherently possess a high Q-factor, enabling good in-band performance and relatively low insertion loss.
• Compact Size: Helical coils achieve a compact form factor by “coiling” the transmission line into a helix, resulting in smaller dimensions compared to traditional cavity or distributed filters.
• Good Out-of-Band Rejection: Capable of providing effective out-of-band rejection, filtering out unwanted frequency components.
• Frequency Tunability (via screw adjustment): Often allows for frequency adjustment within a certain range by turning a screw at the top to change the resonant frequency.
• Cost-Effective: Their relatively simple structure and manufacturing process provide helical filters with a cost advantage in certain applications.
• Moderate Power Handling: Capable of handling moderate RF signal power, suitable for most communication receive and low-power transmit applications.
• Temperature Stability: Performance remains stable within a certain temperature range, though it may be influenced by ambient temperature changes.
• Relatively Easy to Integrate: Typically provided as shielded boxes or packaged modules, making them easy to integrate into PCBs or systems.

Applications

• Wireless Communication Systems:
  • Mobile Radios: Used in Land Mobile Radio (LMR) equipment for channel selection and interference suppression.
  • Walkie-Talkies and Handheld Devices: Widely used due to their compactness and filtering performance.
  • Small Cells and Repeaters: Employed for frequency selection and interference management.
• WLAN (Wireless Local Area Network) and Bluetooth Devices: Provide frequency selection in these devices to differentiate between channels or suppress out-of-band signals.
• GPS/GNSS Receivers: Used to filter out-of-band interference, improving signal reception sensitivity and positioning accuracy.
• Test & Measurement Equipment: Serves as a general-purpose RF filter in laboratory and field testing for signal analysis and selection.
• Remote Control and Telemetry Systems: Used in various industrial, commercial, and consumer remote control/telemetry applications to ensure signal purity.
• Broadcast Receivers: Used for channel selection in certain FM or television receivers.
• Avionics: In avionics systems where size and weight are critical, used for communication and navigation equipment.