Skip to main content

The Role of External Antenna in IoT Applications

External Antenna
Share This Article


The Internet of Things (IoT) is revolutionising industries and reshaping the way we interact with the world. From smart homes to industrial automation, IoT is making our lives more connected and efficient. The performance of IoT devices, however, heavily depends on their ability to communicate effectively. External antennae come into play for some types of areas or building use cases that can be problematic. This article delves into the importance of external antennae for certain IoT use cases, sites, and applications.

External and Directional Antenna: Enhanced Signal Strength and Range

The significant advantage of external and directional antennae is their ability to enhance signal strength and range for some types of devices. Internal antennae, while convenient, often fall short in providing the robust connectivity required for some types of IoT applications. External antennae can be strategically placed to avoid obstructions and optimise signal propagation, ensuring that certain types of IoT devices can communicate over greater distances, deeper inside buildings and structures, and through challenging environments.

For instance, in agricultural IoT applications, sensors deployed across vast fields need reliable connectivity to transmit data to centralised systems. While, for many, low Power Networks or 4g LTE are sufficient, some may require a powered, connected router or gateway, equipped with a weatherproof external antenna to afford the necessary range or local area connectivity. Such set ups, can help bridge gaps by providing the necessary signal strength and range, ensuring that every sensor, no matter how remotely located, can contribute the data for which their deployment was intended.

Another example is where devices or routers are placed within metal enclosures that act as faraday cages. For instance, EV charge points need to be robust, weatherproof, and vandal resistant. In order to overcome the connectivity challenges and signal loss caused by the enclosure, such devices often utilise small foot print and discrete external antennae.

Improved Reliability and Redundancy

In mission-critical applications, such as healthcare and industrial automation, reliability is paramount. External antennae can significantly improve the reliability of some indoor IoT devices by reducing the likelihood of signal interference and dropout. Their ability to be positioned externally allows for better line-of-sight and minimised obstructions, which are common issues with internal antennae.

External antennae can also be used to create redundancy systems for improved reliability. By having multiple antennae, some systems can switch to a backup in case the primary antenna fails, ensuring continuous operation. This redundancy is crucial in scenarios where downtime can result in significant risk, such as in manufacturing plants or emergency response systems.

Flexibility and Customisation

External antennae offer greater flexibility and customisation options. Different IoT applications have varied requirements when it comes to frequency bands, gain, and polarisation. External antennae can be selected and customised to meet these specific needs, optimising performance for the intended application.

For example, in smart city deployments, various IoT devices such as traffic sensors, environmental monitors, and public safety systems might operate on different frequency bands. External antennae with a larger footprint can be tailored to ensure each device operates efficiently within its designated band, facilitating seamless integration and communication across the entire smart city or highway management ecosystem.

Enhanced Performance in Harsh Environments

Many IoT applications operate in harsh weather or physical environments where internal antennae may not suffice. External antennae are usually designed to withstand extreme conditions, including high temperatures, moisture, vibration, and physical abuse. This durability can ensure IoT devices remain operational in the toughest environments.

Empirical Examples and Use Cases

Smart Cities and Highway Management

Smart cities rely on a vast array of IoT devices to manage infrastructure, reduce energy consumption, and improve public safety. From traffic lights and waste management systems to air quality monitors and surveillance cameras, each device needs robust connectivity to function effectively.

External antennae help provide the necessary range and signal strength to ensure these devices can communicate seamlessly across urban landscapes. For example, traffic sensors equipped with external antennae can relay real-time data to traffic management systems, helping to optimise traffic flow and reduce congestion. Parking and ticket machines in remote locations can operate more effectively, and retail payment solutions can overcome ‘dead-spots’ in buildings to ensure the freedom to process transactions right across the service footprint and footfall.

Industrial IoT (IIoT)

In industrial settings, IoT devices monitor machinery, track inventory, and ensure worker safety. These environments often involve metal structures, heavy machinery, and electromagnetic interference, which can hinder signal strength.

External antennae can be positioned and connected to avoid these obstacles, ensuring reliable communications. For instance, in a manufacturing plant, sensors monitoring equipment health can use external antennae to help send data to centralised maintenance systems, enabling predictive maintenance and reducing downtime.


In healthcare, IoT devices play a crucial role in patient monitoring, asset tracking, and facility management. Reliable connectivity is essential to ensure that critical data, such as patient vitals, is transmitted without interruption.

External antennae help maintain strong and reliable connections, even in complex hospital environments with multiple floors and thick walls. For example, wearable health monitors that are connected to external antennae can help continuously transmit patient data to off-site healthcare providers, allowing for real-time monitoring and timely interventions.

Technical Considerations for External Antennae:

Frequency Bands

Different IoT applications operate on various frequency bands, such as 2.4 GHz, 5 GHz, and sub-GHz frequencies. External antennae can be designed to optimise performance for specific frequency bands, ensuring efficient communication for the intended purpose. Examples include LoRaWAN, NB-IoT and 5G.

Gain and Directivity

The gain of an antenna refers to its ability to focus energy on a particular direction. High-gain external antennae can provide more concentrated signals over longer distances, which is particularly useful for point-to-point communication scenarios. This can mean that a mobile radio mast that would normally be on the edge or outside of connectivity, can become in range. It can also mean those that have poor signal and data rates can improve their throughput.


Polarisation refers to the orientation of the electromagnetic waves emitted by an antenna. Matching the polarisation of the transmitting and receiving antennae can significantly improve signal quality. External antennae can be oriented to match the required polarisation, enhancing overall performance for IoT devices. Of course, this can also apply to internal antenna.

Environmental Factors

External antennae are designed to withstand various environmental factors, such as UV radiation, moisture, and physical impacts. This durability ensures that IoT devices remain operational in outdoor and industrial environments where such conditions or events are likely.

Future Trends

The future trends in IoT that highlight the importance of external antennae are considered below:

5G and Beyond

5G networks are designed to support massive IoT deployments with improved capacity, lower latency, and higher data rates. The higher frequency bands used in 5G, however, have shorter propagation ranges and can be easily obstructed by physical barriers. External antennae can help overcome these challenges by providing better signal reception and transmission, ensuring robust connectivity for 5G compatible IoT devices.

Satellite IoT Connectivity

Satellite networks offer a different option to terrestrial networks and can reach remote or marine areas where terrestrial networks are unavailable. External antennae are crucial for establishing reliable connections with satellites, as they need a clear line of sight to receive and transmit signals. Using external antennae designed specifically for types of satellite networks, means IoT devices can communicate with satellites and enable applications such as asset tracking, environmental monitoring, and precision agriculture in areas with limited terrestrial connectivity.

Advanced Antenna Technologies

Advanced antenna technologies like beamforming and MIMO are becoming increasingly important for IoT deployments. Beamforming allows the antenna to focus the signal in a specific direction, improving signal strength and reducing interference. MIMO technology enables multiple antennas to transmit and receive signals simultaneously, increasing data throughput and enhancing overall network performance. External antennae equipped with these technologies can significantly enhance the reliability and range of IoT communications.

The Growth of Industrial and Warehouse IoT

In expanding industrial and logistics hubs, IoT devices are often deployed in challenging environments with high levels of interference and physical obstacles. These facilities typically employ complex and expensive machinery as well as automation and robotic systems. External antennae with rugged designs and higher gain that are deployed on the external building structures can help overcome these obstacles, ensuring reliable connectivity, and minimising signal degradation. This is crucial for applications such as smart factories, asset tracking, and predictive maintenance, where uninterrupted connectivity is essential for real-time data transmission and analysis.

The Importance of External Antennae for 5G Networks and Routers

5G networks are continuing to expand in terms of geographical deployments and functionality. There are several challenges faced by 5G networks, however, in terms of signal propagation. Some of the key challenges are discussed below:

Higher Frequency Bands, Path Loss, Blockage and Reflection:

5G networks utilise higher frequency bands, such as millimetre-wave (mmWave) frequencies, to achieve higher data rates. Higher frequency signals have shorter wavelengths, however, which results in shorter propagation ranges. This means that as the 5G radio signal travels, it experiences path loss, which refers to the reduction in signal strength over distance. As stated, higher frequency signals experience more significant path loss compared to lower frequency signals. 5G signals are therefore more susceptible to attenuation due to obstacles like buildings, trees, and rain. 5G networks, therefore, face challenges in ensuring reliable signal propagation over distance and in areas where attenuating objects, walls or structures, or poor conditions exist.

Interference: Reduced Data Rates, Increased Latency, Degraded Signal Quality, Capacity Constraints and Coverage Limitations.

In dense urban areas or environments with multiple 5G networks operating in proximity, interference can be a significant challenge. Interference occurs when signals from different sources overlap and degrade each other’s quality. This can lead to reduced data rates, increased latency, and overall degradation of network performance. Advanced antenna technologies like beamforming and MIMO can help mitigate such interference.

Addressing these challenges requires a combination of advanced antenna technologies, network planning, and infrastructure deployment strategies. By leveraging techniques like beamforming, MIMO, and optimising network design, 5G networks can overcome these propagation challenges and provide seamless connectivity for IoT applications.

Interference can lead to a decrease in data rates, meaning that the speed at which data can be transmitted and received is reduced. When multiple signals overlap and interfere with each other, the quality of the received signal deteriorates. This results in lower data rates and can affect the overall user experience, especially for bandwidth-intensive applications like video streaming or large file downloads.

Interference can also increase the latency or delay in data transmission. When signals interfere with each other, it can cause delays in the reception and processing of data packets. This delay leads to increased latency, which can be particularly problematic for real-time applications that require low latency, such as retail, video conferencing, or autonomous vehicles.

Interference can cause signal degradation, resulting in poor signal quality. When signals from different sources overlap, they can introduce noise and distortions to the received signal. This can lead to packet loss, errors in data transmission, and reduced signal strength. As a result, the overall quality of the network connection is compromised, affecting the reliability and performance of the 5G network.

Interference can limit the capacity of the 5G network. When multiple signals interfere with each other, the available bandwidth is shared among the interfering signals. This sharing of bandwidth can result in congestion and reduced capacity, leading to slower data speeds and increased network congestion during peak usage times.

Interference can also impact the coverage area of the 5G network. In areas with high interference, the signal strength and quality may not be sufficient to provide reliable coverage. This can result in areas with weak or no signal coverage, leading to connectivity issues and gaps in network availability.

To mitigate the impact of interference, 5G networks employ various techniques such as advanced antenna technologies, beamforming, and interference cancellation algorithms. These techniques aim to minimise the effects of interference and optimise the performance of the network. Additionally, regulatory measures and spectrum management strategies are implemented to allocate frequencies and minimise interference between different wireless networks operating in the same area.


External antennae are not just accessories but critical components that significantly enhance the performance and reliability of IoT devices. As IoT continues to expand into new applications and environments, the role of external antennae will become more important. By providing robust connectivity, external antennae help ensure that IoT systems can deliver on their promise of transforming industries, challenging in-building scenarios, and critical healthcare.

Further Reading: