In modern telecommunications systems, the base station antenna stands out as an undeniable and crucial component to facilitate our daily communication from voice calls to high-speed data transfers. Base station antennas play a fundamental role in wireless communication systems by enabling the signal transmission and receival between the base stations and mobile devices.
Base station antennas are also known as cell site antennas and cellular antennas, and they are typically mounted on a tower or rooftop and connected to a base station through coaxial cables. Base station antennas are available in different shapes and sizes and can be either omnidirectional antennas or directional antennas. The operating frequency, coverage area, range, and other performance parameters can vary depending on the base station antenna that is chosen for a specific network.
Different communication systems will use different base station antennas such as GMRS (General Mobile Radio Service) base station antennas, generally used for two-way communication systems for personal and emergency applications, CB (Citizens Band) base station antennas generally used for short-range personal and commercial radio systems, VHF (Very High Frequency) base station antennas commonly used for marine, aviation, and public safety communications systems and UHF (Ultra High Frequency) base station antennas commonly used for mobile communications, military systems, and broadcasting systems etc.
This article will provide a thorough outlook on base station antennas from working principles, applications, installation and maintenance details and everything in between.
How do base station antennas work?
Base station antennas work by transmitting and receiving electromagnetic waves. When users access the network to either make calls or transfer data, the signals will be sent to the nearest base station where the base station antenna then would convert the received signal to an electrical current which will be amplified before sending to the base station equipment. Inside the base station equipment, the signal will be processed to establish the connection and enable the call or access to internet resources. Conversely, when a base station antenna wants to send signals to users, the antenna converts the electrical current into an electromagnetic wave and transmits it.
The base station antenna would radiate the signals in specific directions based on its radiation pattern and the coverage area will also be determined by the directionality on the base station antenna. Generally these base station antennas are mounted on towers or on rooftops to achieve desired coverage area and to minimize the interference. This will ensure maximum signal strength and quality. Overall, base station antennas perform the function of converting electric signals to electromagnetic waves and vise versa, thus facilitating the connection between the base station and the user devices.
Types of base station antennas
As discussed, base station antennas are a critical component to ensure seamless connectivity in communication systems that are used daily by consumers. There are various types of base station antennas that can be used based on the specific requirements of a network. A few of the most commonly used types of base station antennas are discussed briefly below.
- Omnidirectional fiberglass antennas
Omnidirectional fiberglass base station antennas transmit and receive signals equally in all directions. They are used in networks where the consumers can be located in any direction in a circular area around the antenna. Typically, these antennas are used in low-density urban areas or rural areas where either the direction of the users is unknown, or directions could change in all directions. Omnidirectional base station antennas have a large coverage area as they can transmit and receive signals over 360 degrees, however their gain is low and hence lower signal strength and shorter range. Fiberglass outer covering ensures that these antennas can be conveniently used for outdoor applications as they will be resistant to most weather conditions.
- Sector antennas
Sector type base station antennas radiate signals in a specific direction in the horizontal plane. The coverage area of these antennas is typically between 60 degrees to 120 degrees but could extend further. Due to their directionality, sector base station antennas have a comparatively higher gain. Hence they have a high gain and therefore better signal strength and longer radiation distances or ranges. Sector base station antennas are ideal to set up wireless networks in high density urban areas. These antennas can be combined to form multi sector antennas in order to improve the coverage area.
- Yagi-Uda antennas:
Yagi antennas are highly directional antennas and they are ideal to be used as base station antennas. Yagi antennas consist of a dipole element in a long boom-like structure and several parasitic elements that are attached on either side of the boom structure to enhance the radiation in one direction. Due to the high directionality of Yagi antennas, they are ideal to set up networks that require the coverage area to be along a long distance but in a small, focused area. As Yagi antennas are highly directional and have a high antenna gain in a specific direction, they are more resistant towards interference from other devices or obstructions in the environment. These antennas are generally suitable for long distance communication systems and wireless networks in rural or suburban areas.
- Parabolic dish antennas:
Parabolic dish antennas are used as base station antennas as they have the ability to focus signals into a specific direction and have high directionality. These antennas are ideal for long-range communication systems, for point-to-point links between base stations and for satellite communication. The parabolic shape allows these antennas to generate a narrow focused strong signal beam towards a fixed direction and hence can facilitate high data rates with minimal interference.
- Dipole antennas:
Dipole antennas are one of the simplest and widely used antennas. They can be used as base station antennas, and they generally consist of two conductive elements separated at the center with an insulating material. The signal source is provided to the center of the antenna and then the voltage & current supplying throughout the two conductive elements generate electromagnetic signals that are radiated outside of the antenna. Dipole antennas are omnidirectional and hence can be used at base stations that need to transmit or receive signals equally in all directions. VHF & UHF dipole antennas can be used in base stations to establish connectivity for public safety, coastal areas, industrial & public communication applications.
Different frequency bands used
Base station antennas are a fundamental component in the day-to-day communication systems that we use. Hence the performance of these antennas can have a significant impact on the quality of the communication system and the user experience. Based on the different applications and use cases, antennas of different frequencies might be required. Some of the commonly used frequencies in base station antennas are discussed below.
700 MHz: This frequency is used for Long Term Evolution (LTE) networks and can provide good coverage and capacity.
900 MHz: This frequency is generally used for Global System for Mobile Communications (GSM) networks and offers good coverage, but lower data rates compared to higher frequencies.
1800 MHz: This frequency is also generally used for GSM networks but unlike the 900 MHz frequency, this provides higher data rates but with reduced coverage.
2100 MHz: This frequency is generally used for Universal Mobile Telecommunications System (UMTS) networks and offers higher data rates but with limited coverage.
2600 MHz: This frequency is another frequency that is used for LTE networks and provides very high data rates but as frequency increases the coverage area gets limited even more.
3500 MHz: This frequency is generally used for modern 5G networks and offers high data rates but with limited coverage.
5800 MHz: This frequency is used for Wi-Fi networks and offers high data rates but with shorter wavelengths, they are more suited for short-range communication.
Thus, as it can be seen, the operating frequency range for a base station antenna must be carefully chosen based on the application requirements optimizing between data rates, transmission range and coverage area.
MIMO and Beamforming Antenna Technologies
MIMO and beamforming technologies have become a crucial part in modern network systems. Base station antennas can be used in MIMO configuration where the number of transmitters and receivers will be increased in the network and will be able to send and receive signals over the same channel simultaneously thus increasing the capacity without sacrificing spectrum.
In beamforming, multiple antennas send the same data across multiple streams. But due to the different placement and location of the antenna, at certain points the signals will coincide improving the signal strength and in other areas it might weaken the signal. By strategically placing the base station antennas to optimize with the phase differences, the overall signal strength of the transmission can be enhanced.
What are base station antennas used for?
As highlighted throughout this article, base station antennas are extremely important in the communication systems. Discussed below are some of the most common use cases of base station antennas.
Wireless Communication Networks (e.g., Cellular Networks such as 2G, 3G, 4G, 5G)
Base station antennas play a major role in establishing the wireless connectivity between end user devices such as mobile phones or tablets and the network infrastructure in cellular networks. Within the coverage area of the base station antenna, it will receive and transmit signals between the user devices and the base stations of the wireless network. Different generations of cellular networks 2G, 3G, 4G or 5G will use base station antennas operating at different frequency bands to transmit and receive signals that carry voice, data, text etc. Generally, 2G (GSM) networks use low frequency bands such as 900 MHz and 1800 MHz, 3G (UMTS) networks generally operate at higher frequencies like 2100 MHz, 4G (LTE) networks use a wide range of frequencies such as 700 MHz, 1800 MHz, and 2600 MHz while 5G networks can use an even broader range of frequencies from sub-1 GHz (low band) to higher frequencies such as mid-band (3.5 GHz) and even millimeter-wave frequencies (24 GHz and above). 5G cellular networks require faster data rates and quality connectivity and hence such networks use base station antennas that operate with latest technologies such as MIMO (Multiple Input Multiple Output) and beamforming.
Signal Coverage
Base station antennas are the primary component for providing signal coverage in a wireless network. The coverage area depends on the type of antenna used and the performance parameters of the antenna such as the frequency, gain, polarization etc. In order to get the optimized coverage area of a base station antenna, it should be carefully and strategically placed such that the interference is minimized from other surrounding devices as well as the environmental conditions. To ensure seamless connectivity for users when they move, generally the base station antennas are placed such that the coverage areas of the two nearby antennas slightly overlap. Signal coverage area of a base station antenna can vary from a suburb to large cities or large rural areas. Both omnidirectional antennas and directional antennas can be used as base station antennas and the signal coverage from an omnidirectional antenna will be in all directions equally while if a directional antenna such as a dish antenna or a sector antenna is used, the signal coverage will be focused towards one specific direction. If directional antennas are used, they can be used in a network targeting different sectors or directions such that a larger signal coverage is achieved.
Backhaul Connections
The connection between a base station and the core network that connects multiple base stations together is known as a backhaul connection. Backhaul connections can be either wired or wireless. Base station antennas play a key role in backhaul connections by establishing the point-to-point connections between base stations or between the base stations and the core network. This is extremely useful especially in locations where it is not feasible to install wired infrastructure. Highly directional antennas are suitable for backhaul connections as they can ensure that the connections are securely established even over longer distances and through any interference that might occur.
Broadcasting (FM Radio and Television Signals)
Another major use case of base station antennas is for broadcasting FM radio and television signals. In FM radio broadcasting, generally the base station antenna will transmit radio signals to all directions as an omnidirectional antenna such that all devices from all directions, within a specific region will be able to connect and receive the radio wave signals. In television broadcasting, similarly the television channels or content will be transmitted to users via the base station antenna. Along with the commonly used operating frequencies for base station antennas, television signal broadcasting might require base station antennas of VHF and UHF ranges. Base station antennas for FM radio and television broadcasting ideally should be optimized to transmit signals in all directions without sacrificing the range/distance of transmission.
Emergency and Public Safety Communications
Base station antennas can also be used in emergency and public safety communication systems such as natural disaster response systems, accidents, military bases etc. Base station antennas are used in these emergency response systems as they can provide stable and reliable connectivity with high signal strength and quality. These antennas are used widely by first responders, medical teams, military teams etc. Reliable and stable communication allows to have proper coordination between users to ensure that an emergency or threat is safely and smartly handled. Base station antennas are also typically used in alert and warning systems to effectively notify users within a specific coverage area to ensure public safety.
Role in Cellular Networks
Base station antennas are the most crucial elements in cellular networks. They are used for the transmission and receival of signals across all generations of cellular networks from 2G to 5G and beyond. Each generation of cellular network uses a different technology such as GSM with 2G, WCDMA with 3G, WiMax and LTE with 4G and MIMO and millimeter wave technology with 5G. Each of these technologies can be established using base station antennas with different operating frequencies.
As the cellular network generations evolve, so do the technologies and standards used with them improve. Better speeds, better data rates, better signal quality and overall better performance is expected of the cellular networks as the technologies develop rapidly. Hence, base station antennas play a fundamental role in ensuring stable and reliable communication in the cellular networks and offering users a seamless experience during voice calls, texts, streaming etc.
Along with the performance characteristics, the coverage area for a cellular network will also be determined based on the type of base station antenna used. Whether the signal radiation is for all directions like in omnidirectional antennas or whether it is a focused beam as in directional antennas and the transmission range will all be impacted by the base station antenna chosen to establish the cellular network. Hence, it is important to pay careful attention when selecting a base station antenna for a cellular network of any generation.
What are VHF/UHF Dual band base station antennas?
Dual band base station antennas have the ability to operate on two separate bands or frequencies. They can either operate on one frequency band or on both frequency bands simultaneously based on the requirement of the user devices in the network. VHF range is generally considered between 30 and 300 MHz while UHF range is considered between 300 MHz and 3 GHz. In these dual band base station antennas, they have the ability to utilize both of these frequency bands, thus making them much more versatile for a wide range of applications.
What are CB Base station antennas?
Citizen’s Band base station antennas are typically used for short to medium distance communications and generally operate in the frequency range of 26.965 MHz to 27.405 MHz. These antennas can be either omnidirectional or directional antennas and they are available in a variety of shapes and sizes. CB base station antennas are specifically designed to ensure effective transmission and reception of CB radio signals to provide consistent, reliable and high-quality communication between CB radio devices.
Impact on Network Performance
The antenna is probably the biggest contributor in determining the performance of a network. Base station antennas also have a huge impact on the overall performance of the network, they are generally have a higher gain compared to other types of antennas and hence they can transmit over longer distances and at better speeds and higher data rates. Base station antennas are typically designed to provide high quality signals with minimal interference and noise. These antennas can help ensure a stable and reliable connection.
Since base station antennas are available in all types, it provides the flexibility to use an antenna based on the needs of a specific network and to optimize coverage and signal strength in each network. Also, base station antennas are designed to allow a massive amount of users to connect simultaneously making them ideal to use in situations with high population density or heavy network usage. Base station antennas are durable and are able to withstand even harsh weather conditions and hence reliable and stable connectivity and network performance can be ensured regardless of any extreme weather conditions.
Overall, base station antennas play a major role in providing high quality wireless connectivity and network performance.
Base Station Antenna Placement
The placement of a base station antenna is extremely important to achieve the optimal performance of it. The location for the antenna should be chosen such that it has minimal interference from any surrounding other antennas or devices as well as any significant physical obstructions.
It is also important to pay attention to the weather conditions of the operating environment. In urban areas, with high population density, generally directional antennas with relatively low gain and narrow horizontal beamwidth are ideal in order to minimize interference. In rural areas, since they have lower traffic volumes, high-gain directional or omnidirectional antennas are used since coverage is a major concern.
Antenna Maintenance
The maintenance of base station antennas is critical to ensure that the antennas operate optimally. This is important in providing the end users with a reliable and stable communication system. Base station antennas require regular checkups in order to ensure that their performance parameters are maintained. Routine maintenance should include visual inspections, cleaning, and testing of the antenna system.
Cost Considerations
When selecting a base station antenna, the cost is a key consideration. It is important to consider the overall costs that might be involved during initial set up as well as long term maintenance. The actual cost will depend on the type of antenna chosen and its performance characteristics. However, it is important to be mindful in having a balance between the amount spent and the level of performance achieved from the base station antenna in the network.
Conclusion
This article provided a comprehensive overview on base station antennas, highlighting how they work, different types and models available, latest technologies involved and some of the common use cases. Base station antennas are critical in establishing cellular networks and this article discusses the different generation of cellular networks, the main technologies in each generation and how different base station antennas with different frequencies can be used to fulfill the requirements of a network.
The article also touched on a few of the factors to consider when selecting an antenna such as the placement, maintenance and cost. Overall, a thorough understanding of the base station antennas, their operation and the wide range of options available will allow us to achieve the optimal performance of the antenna for a network.
