NB-IoT Antenna

There are three main types of IoT antennas available on the market: built-in patch antennas, suction cup vehicle-mounted antennas, and screw-mounted external waterproof antennas.

The NB-IoT antenna shown in this article belongs to the screw-mounted outdoor waterproof antenna category. It is specially designed for industrial electrical control cabinets, outdoor integrated equipment boxes, and municipal IoT terminals.

Qianmu Communication's cabinet external NB antenna supports full-band NB-IoT from 700MHz to 960MHz and is compatible with narrowband networks of the three major operators: China Mobile, China Unicom, and China Telecom. It is available with two common screw sizes, M12 and M16, matching the installation hole standards of most domestic and imported industrial cabinets.

What is an external antenna for NB-IoT cabinets

An NB-IoT cabinet external antenna is a screw-mounted waterproof RF antenna designed for industrial IoT equipment. It is installed externally on equipment cabinets to provide stable wireless signal transmission for NB-IoT terminals in outdoor and industrial environments.

Working Principle

Many customers mistakenly believe that an antenna is only a metal oscillator and that the waterproof housing has no impact on signal performance. In fact, the structural design of the NB-IoT cabinet external antenna directly affects the stability of long-distance outdoor communication. The working performance can be tested and verified through vector network analyzers and shielded anechoic chambers.

1. Low-Frequency Oscillator Resonant Structure

NB-IoT operates in the 700–960MHz low-frequency communication band, which has longer wavelengths and higher requirements for oscillator length and ground matching. The antenna uses segmented copper radiating elements inside, accurately matching narrowband low-frequency resonance and avoiding resonance offset and standing wave increase found in ordinary short antennas.

2. Cabinet-Isolated Radiation Structure

The antenna is installed outside the cabinet. The metal screw is used for fixing and ground coupling, while the oscillator maintains a safe isolation distance from the cabinet sheet metal. This avoids RF signal shielding and absorption caused by the metal enclosure.

For the same specification, a built-in antenna installed inside a metal cabinet may experience 6–9dB attenuation, while the external NB-IoT antenna has an overall attenuation of only 1–2dB.

3. Multi-Layer Sealed Waterproof Structure

The antenna adopts a rear waterproof silicone gasket, threaded waterproof rubber ring, and injection-molded lead-out wire structure to provide three layers of protection. Rainwater and condensation cannot enter the cabinet along the cable. The 50Ω coaxial cable maintains stable RF signal transmission and prevents impedance drift caused by outdoor temperature changes.

4. Noise Suppression Structure

The antenna base adds a ground coupling ring to filter electromagnetic noise generated by power supplies, PLCs, and relays inside the cabinet, reduce noise levels, and improve the success rate of IoT terminal base station access.

Compatible Equipment

The NB-IoT antenna is designed for IoT terminals that require metal cabinet protection and long-term outdoor operation. It is suitable for civilian, commercial, and industrial devices:

1. Smart Remote Transmission Water Meter Cabinets

Municipal water and gas equipment, gas collection boxes, pipeline pressure monitoring and control cabinets, and online water quality monitoring equipment.

2. Smart Power and Industrial Control Equipment

Outdoor power collection cabinets, low-voltage distribution monitoring terminals, photovoltaic energy storage integrated control cabinets, and electricity meter concentrators.

3. Smart City Security Equipment

Road dust monitoring boxes, environmental and weather monitoring stations, parking barrier control cabinets, and outdoor street lamp smart controllers.

4. Industrial Automation Terminals

Factory workshop data acquisition control boxes, warehouse logistics positioning terminals, and equipment fault wireless alarm cabinets.

5. Agricultural IoT Equipment

Field soil monitoring cabinets, aquaculture water quality control cabinets, and greenhouse environment integrated monitoring equipment.

Detailed technical parameters table

Common FAQ Section

Q1: Can the cable length and connector of the external NB-IoT antenna be changed?

A: Yes. The standard models support coaxial cable lengths from 1.5m to 10m. Connectors such as SMA, IPEX, and N can be replaced according to requirements. Bulk orders also support custom shell colors and LOGO silk-screen printing.

Q2: Is this outdoor NB antenna compatible with China Mobile, China Unicom, and China Telecom NB cards at the same time?

A: Yes. The antenna covers the full 700–960MHz NB-IoT frequency band and is compatible with the NB networks of the three major operators. There is no need to purchase separate versions for different frequency bands.

Q3: Will wire bending affect the antenna signal when the cabinet interior space is limited?

A: The cable can be gently bent with a large bending radius, but 90-degree bending and repeated folding should be avoided. During installation, keep the cable as straight as possible and away from interference sources such as power supplies and frequency converters to prevent significant signal attenuation.

Q4: Is the metal nut of the antenna prone to rust during long-term use in coastal salt spray environments?

A: No. The antenna locking nut is made of passivated anti-rust aluminum alloy and has passed a 48-hour salt spray test. It is not prone to rust or jamming during long-term outdoor use in coastal areas. For highly corrosive environments, engineers can be consulted for customized anti-corrosion solutions.