FAQs – Other RF Components

RF filters selectively allow or block certain frequency ranges, ensuring clean signal transmission and reception. They’re critical for minimizing interference between different wireless technologies and improving overall system performance.

• Band Pass: Passes signals within a specific frequency band and attenuates signals outside it.
• Low Pass: Allows signals below a certain cutoff frequency to pass, while higher frequencies are attenuated.

• Frequency Range: The span of frequencies where the filter operates effectively.
• Bandwidth: The width of that passband or cutoff region; larger bandwidth can accommodate broader signals, but narrower bandwidth can offer more precise filtering.

• Connectorized: Ideal for test setups or external modules that require easy plug-and-play or field replacement.
• SMD/SM: Suited for compact PCBs and high-volume production, reducing overall assembly costs and size.

These entries specify the operating frequency range (e.g., 1560–1608 MHz) and the bandwidth (e.g., 10 MHz) the filter passes. A filter with 915 MHz center frequency and 725 MHz bandwidth suggests it can handle signals spanning from well below 915 MHz up to above it, depending on the filter’s design.

A diplexer is a two-port filter network that splits or combines signals into separate paths based on their frequency bands. It allows multiple RF signals (e.g., GNSS and cellular) to share a single antenna without interfering with each other.

These ranges indicate where each port operates. For instance, a diplexer might route signals between 1166–1610 MHz to one port and another frequency band to the second port, enabling simultaneous multi-band communication.

“None” typically indicates the diplexer port isn’t applying an additional filter (e.g., bandpass or low pass) to that particular path. In other words, that path might pass a broader range of frequencies, relying on the complementary filter in the other path to manage interference.

Surface-mount diplexers are easy to integrate on PCBs, reducing manufacturing complexity. They’re also more compact, lighter, and often have better electrical performance at high frequencies due to shorter lead lengths.

An RF front end module combines essential RF circuitry—like low-noise amplifiers (LNAs), filters, and switches—into one package. This streamlines design, reduces PCB space, and ensures optimized performance for specific wireless applications (e.g., GNSS, cellular).

These notations refer to specific GNSS frequency bands used by different satellite constellations.

• L1 (~1575 MHz) is the most common GPS frequency.
• L2 (~1227 MHz) and L5 (~1176 MHz) support more precise or robust signals.
• L-Band often covers a broader range around these frequencies, including correction services like SBAS.

• L1/L2/L5: Covers three major GNSS frequencies, offering enhanced accuracy and redundancy.
• L1/L5: Supports two frequencies for improved precision over single-frequency designs.
• L1/L5/L-Band: May include additional correction signals or SBAS data within the L-Band range.

• Frequency Coverage: Ensuring the module supports all required bands (L1, L2, L5, etc.).
• Noise Figure: Lower noise means better sensitivity.
• Filter Integration: Built-in filters reduce board complexity and interference.
• Size & Power: The module should fit the device’s form factor and power constraints.

A 3 dB hybrid coupler splits an incoming signal into two equal-power outputs, each at half the input power (minus small insertion losses). It also isolates signals in the reverse path, allowing clean combining or splitting of RF signals.

Hybrid couplers are frequency-dependent. Operating them outside their specified range can degrade isolation, power division accuracy, and return loss, resulting in lower overall system performance.

• Antenna Sharing: Combining signals from multiple antennas or dividing signals to multiple paths.
• Balanced Amplifiers: Splitting input power into two amplifier paths for increased output.
• Phase Shifting: Creating specific phase relationships in phased-array antennas or beamforming systems.

Insertion loss reduces the signal strength through the coupler. Designers must choose couplers with low insertion loss to maximize efficiency and ensure sufficient power reaches downstream components or