Multi-band Combiners

Key performance parameters for a multi-band combiner include insertion loss, isolation, return loss, band pass characteristics, Passive Intermodulation (PIM), and power handling capacity. PIM is crucial because high PIM levels can cause signal interference and degrade performance. Power handling capacity is important to ensure the combiner can handle the maximum power levels without damage or loss of signal quality.

In a MIMO (Multiple Input Multiple Output) system, a double unit multi-band combiner can be crucial because it allows for the simultaneous handling of multiple signals across different frequency bands. This setup ensures effective combining and isolation of signals from various antennas, which is essential for maximizing data throughput and maintaining signal integrity in complex MIMO systems. By using double unit (or called twin unit), each band can be processed independently, enhancing overall system performance and reducing interference between different MIMO channels.

A multi-band combiner and a same-band combiner are designed for different RF signal configurations.

A multi-band combiner combines signals operating in separate, non-overlapping frequency ranges into a shared RF path. For example, signals from 700 MHz, 1800 MHz, 2100 MHz and 2600 MHz systems may be combined before transmission through one feeder cable or antenna network. Frequency-selective filtering helps maintain separation between the connected bands while reducing the number of feeders and passive devices required.

In contrast, the same band combiner is used when two or more RF inputs operate within the same or overlapping frequency range. These products are commonly selected for combining signals from different base stations, operators or sectors that cannot be separated by conventional frequency filters.

The right choice depends mainly on the relationship between the input frequencies:

• Choose a multi-band combiner when the signals operate in clearly separated frequency bands.

• Choose same band combiners when multiple inputs operate within the same or overlapping frequency range.

• Consider hybrid combiners when broad frequency coverage and strong isolation between signal sources are required.

For passive DAS, outdoor cellular sites and shared feeder systems, reviewing the input frequency ranges, power levels, port isolation, insertion loss and PIM requirements will help determine the most suitable combiner configuration.

1. Low PIM: Typical third-order PIM of –153 dBc or better, meeting the demands of multi-carrier base station environments.

2. High Band Isolation: ≥ 50 dB isolation between adjacent frequency bands to prevent signal leakage and interference.

3. Low Insertion Loss: ≤ 0.5 dB per band path, preserving signal strength across all combined frequencies.

4. DC Bypass Support: Available on all ports, enabling remote electrical tilt (RET) and AISG compatibility for tower-mount applications.

5. Wide Frequency Coverage: Supports bands from 380 MHz up to 5925 MHz, covering GSM, LTE, NR Sub-6G, and C-Band.

6. Weatherproof Construction: IP67-rated enclosures for outdoor tower and rooftop installations.