5G Measurements: Understanding Directional and Omnidirectional Antennas
The Role of EMF Measurements in 5G Communication
In today's world, wireless communication has become an integral part of our daily lives, with 5G broadband technology leading the way in providing faster and more reliable connectivity. The deployment of 5G technology has increased the need for measuring electromagnetic fields (EMF) to ensure optimal signal coverage and safety for the public. As 5G continues to expand and revolutionise the way we communicate, measuring EMF radiation, which is emitted by wireless technology, will become increasingly important for ensuring public safety and mitigating any potential health risks associated with wireless communication technologies.
The Difference between Directional and Omnidirectional Radiation
To accurately measure electromagnetic field waves, it is crucial to have a fundamental understanding of how EMF radiates electromagnetic waves. This knowledge plays a vital role in assisting radiation professionals in selecting the appropriate instrumentation for measuring EMF radiation.
Electromagnetic radiation can be classified as either omnidirectional or directional based on how it propagates in space.
Directional EMF radiates electromagnetic waves in a specific direction and can provide a stronger and more focused signal than omnidirectional EMF. This type of radiation propagates in a beam that is concentrated in a particular direction, rather than spreading out equally in all directions. Due to its propagation characteristics, directional radiation can be used to transmit signals over long distances, such as in satellite communication or long-range wireless networks. They are well-suited for long-range or high-capacity communications and can be aimed and pointed with precision to optimise signal coverage and strength. The use of directional EMF depends on the specific requirements of the deployment and the desired trade-offs between signal strength, coverage, and cost.
Omnidirectional EMF on the other hand radiates electromagnetic waves equally in all directions and can provide reliable and consistent signal coverage over a wide area without the need for precise directional aiming. This type of radiation spreads out equally in all directions, creating a spherical wave front. They are well-suited for providing coverage in indoor areas or for small cell deployments and can cover a large area with a consistent and uniform field. However, they may suffer from interference or signal degradation caused by obstacles or other sources of electromagnetic radiation and may not provide as strong or focused a signal as directional antennas. Additionally, they may require additional power to achieve the same signal strength, which can increase operational costs.
Monitoring and Measuring 5G EMF with Directional and Omnidirectional Antennas
There is a wide range of instrumentation available that has been specifically designed for monitoring EMF exposure levels. To monitor electromagnetic radiation frequencies, devices such as spectrum analysers, which can detect and measure the strength of electromagnetic radiation across a range of frequencies, are commonly used to detect directional and omnidirectional radiation.
The key to measuring omnidirectional and directional EMF is ensuring users select the best suited probe for the application required. The Narda Safety Test Solution 5G FR2 Antenna is designed to be used with the Narda SRM-3006 Spectrum Analyser. It is a specialised antenna designed for measuring the electromagnetic fields of high frequency 5G wireless networks operating in the frequency range of 24.25-29.5 GHz.
Designed to be lightweight and portable, making it easy to use in the field, the antenna is available in two models that differ in their reception characteristics. Model 3591/01 features a directional characteristic and is highly sensitive, while the Model 3591/02 offers an omnidirectional characteristic. Both antennas include a downconverter that converts the millimetre wave band from 24.25 GHz to 29.5 GHz into the SRM-3006’s receive band.
Omnidirectional and Directional (Horn) Antenna
Omnidirectional Antenna
National and international standards recommend isotropic measurements for monitoring EMF. Unfortunately, isotropic antennas are currently not available for the FR2 frequency range. As an alternative, the Narda antenna 3591/02 offers an omnidirectional reception characteristic that closely resembles that of a donut shape which is the closest available option to an isotropic characteristic in the FR2 frequency range.
To achieve optimal results with the 3591/02 antenna, it is recommended to perform measurements in an X-Y spatial plane. However, since isotropic measurements require coverage of all three spatial axes, the antenna must be moved accordingly during the measurement process. By holding the omnidirectional antenna vertically upwards, the antenna can also effectively detect higher base stations due to its wide opening angle in the Z-direction. The omnidirectional antenna is ideal for on site compliance measurements and boundary testing.
Directional (Horn) Antenna
The directional antenna, also known as a horn antenna, is ideal for low field strength measurements. An example of this is behind a window. A coated glass window can attenuate a signal at 24 GHz by about 30 db. To be able to detect such a field strength, a high gain antenna such as the Narda FR2 Directional Antenna is required. Furthermore, the directional characteristic of the antenna can be utilised to assess the field strength of geographically separated base stations. Depending on the orientation of the antenna, it can primarily receive either horizontally or vertically polarised RF signals. This allows for targeted measurements and analysis of specific signal orientations, providing valuable insights into the strength and distribution of electromagnetic fields in different directions.
An important tool for ensuring the safety of 5G wireless networks and mitigating potential health risks associated with high-frequency EMF radiation, the 5G NR FR2 Antenna is used by regulatory agencies, network operators, and other organisations to verify compliance with safety standards and guidelines, and to monitor the electromagnetic environment in various settings.
The monitoring and regulation of EMF levels in Australia falls under the jurisdiction of the Australian Radiation Protection and Nuclear Safety Agency (ARPANSA), which is responsible for setting and enforcing safety standards for EMF radiation such as the Radiation Protection Standard for Maximum Exposure Levels to Radiofrequency Fields. ARPANSA also provides information and advice on EMF safety and conducts research on the potential health effects of EMF radiation.
The Narda SRM-3006 Spectrum Analyser and FR2 Antennas are available in Australia exclusively from Air-Met Scientific.
