An antenna is a component used to transmit or receive radio waves. For devices connected wirelessly, the performance of an antenna receiving and transmitting radio signals will have a decisive impact on the efficiency and rate of wireless communication. This article outlines some technical concepts and types of antennas, as well as the product features of the 2.4GHz/5GHz dual-band external antennas introduced by Molex.
Vital to Any Radio Communication Device is the Antenna
The basic structure of wireless communication is mainly composed of a transmitter and a receiver. The transmitter is responsible for encoding voices, videos and various data into sinusoidal electromagnetic waves and sending them out. The receiver will receive and decode these electromagnetic waves to obtain data. Both the transmitter and receiver need to use antennas when transmitting signals. An antenna is the device that converts the electric field into an electromagnetic wave.
The antenna is the medium between radio waves for movement and propagation of electrons in the conductor in space. During transmission, the transmitter will apply a current to the antenna to generate a radiated electromagnetic field, changing the energy of the current into radio waves. During reception, the antenna will generate a current inside the antenna due to the induction of an electric field, and generate voltage at its terminal, generating electrical signals in the receiver. Antennas are widely used in communication systems such as broadcasting, point-to-point radio communication, radar and space exploration. Antennas are essential components in radio communication systems.
Selecting the Right Antenna - The Critical Move
According to the radio wave radiation mode, the types of antennas can be divided into two basic types: omni-directional antennas and directional antennas. Omni-directional antennas radiate uniformly in the plane, and directional antennas can radiate more in a certain direction. In free space, any antenna can radiate energy in all directions, but the specific architecture will make the antenna obtain greater directivity in one direction, while the energy radiation in other directions can be ignored.
The omni-directional antenna transmits and receives radio signals equally in all directions. The effective signal mode of the omni-directional antenna looks like a ring, and the antenna is located at the central point. The omni-directional antenna is used by mobile phones. When the wireless device is located at the center of the star topology, the omni-directional antenna is most suitable. For long-distance point-to-point communication, the directional antenna is best.
A directional antenna is to arrange multiple metal components in the same physical plane to concentrate most of the energy of the transmitter or receiver in a single direction. Directional antennas are usually used outdoors for long-distance signal transmission.
In addition, antennas can also be divided into external antennas and built-in antennas. As the name suggests, an external antenna is an external antenna independent of the motherboard. Compared to an external antenna, there are also built-in antennas such as PCB antennas, FPC antennas and LDS antennas, which have their own unique product forms. PCB antennas are widely used in the circuit boards of single frequency band modules such as Bluetooth modules, Wi-Fi modules and ZigBee modules. Its cost is very low. After debugging once, there is no need to debug again, but it is only suitable for a single frequency band; FPC antennas are equivalent to pulling out the antenna line on the PCB and using other external metal as the antenna, which is usually used in low-end mobile phones and intelligent hardware products with complex frequency bands; LDS antennas are an evolutionary version of FPC antennas, with high space utilization. LDS antenna are formed by direct structuring of the antenna pattern onto a molded device using laser, which make them very suitable for applications with tight internal space. These type of antennas have their distinct advantages and disadvantages, and the appropriate antenna can be selected depending on the specificity of the applications.
Optimizing Your Wireless Network Performance With The Right Antenna Solution
Antennas are an important part of wireless communication. A suitable antenna can optimize the wireless network and increase the communication range and reliability, the reverse of this will mean a decline in communication quality. When selecting an antenna, you must understand a variety of antenna parameters such as frequency, matching impedance, voltage standing wave ratio (VSWR), gain, radiation efficiency value and polarization and the characteristic of the devices using them.
The operating frequency of the antenna is the most critical parameter. Taking Wi-Fi applications as an example, the operating frequency band of the first-generation IEEE 802.11 and second-generation IEEE 802.11b is 2.4GHz. The third-generation IEEE 802.11a extended to 5GHz, and the fourth generation IEEE 802.11n (aka Wi-Fi 4) includes both 2.4 and 5GHz frequency bands. The fifth generation IEEE 802.11ac (aka Wi-Fi 5) is 5GHz, and the sixth generation IEEE 802.11ax (aka Wi-Fi 6) is a substantial upgrade over previous generations as it allows for potentially faster connection speeds in addition to the currently supported 2.4 and 5GHz bands. Therefore, dual-band antennas that can support both 2.4 and 5GHz can make promising candidates to supporting a growing range of speedier Wi-Fi devices with each new generation.
Another common parameter of the antenna is the gain. The antenna gain represents the degree of energy concentration of the antenna to the signal and the conversion efficiency. Increasing the gain of wireless communication is not to amplify the signal, but to gather the energy of the signal. The gain can affect the direction of antenna operation. Generally speaking, the higher the gain, the stronger the directivity of the antenna. When the gain is lower, the more uniform the radiation distribution in all directions.
Often manufacturers of antennas emphasize high-gain antennas. But in fact, are high-gain antennas really an advantage? It still depends on the applications. If you know exactly where your desired signal is coming from, and you want to get the maximum gain direction, a high gain antenna will have an advantage. However, if you don’t know the source and direction of the desired signal, it is better to have a low gain antenna.
Wi-Fi networks are relied on so heavily for IoT applications that the resulting network congestion and RF complexity often leads to degraded performance and reliability. The solution to address these demands with the adoption of dual-band Wi-Fi. Adding the 5 GHz spectrum provides dramatically higher performance and more reliable connections, which can significantly improve network connectivity even in highly congested IoT environments such as industrial facilities, hospitals, and manufacturing plants.
High Quality Wi-Fi Dual-Band Antenna Solutions for IoT Applications
Molex produces a variety of ready-to-use radio frequency (RF) antenna products, which are compact in structure, excellent in performance, and available in a variety of form factors. They are applicable to all standard antenna protocols and frequencies. They can help customers provide perfect support and diverse solutions from concept to product completion.
The Molex 215868 series Wi-Fi On-metal antenna is an external antenna with a frequency range of 2.4-2.5 GHz and 5.15-5.85 GHz. This dual-band antenna can be mounted on metal surfaces without compromising RF performance. The antenna size is only 44 x 37 x 8.5mm, with an RF power of 2W, and an impedance of 50Ω. Performing well on metal substrates, its self-adhesive mounting makes for easy installation and provides U.FL (MHF compatible) connector options at the terminating cable end. Both cables and connectors can be customized according to specialized needs, if required. IPX7 waterproofing is supported.
Molex's 2.4 GHz/5 GHz Wi-Fi on-metal antenna - 215868 series, comes with a 300.00mm micro coaxial cable and is compatible with use at the U.FL/I-PEX MHF connector end. Idea for compact Internet of Things (IoT) devices, the antenna is an excellent choice for supporting Wi-Fi, Bluetooth and ZigBee communication protocols. It can be installed with adhesives and screws for more robust mounting. Weighing a mere 7.040g, this low-profile antenna is linearly polarized and omni-directional. It is offered in tray packaging. It has an operating temperature range of -40 to +85℃, making it suitable for sub-zero temperature environments. The antenna has a peak gain of 2.0 dBi (at 2.4 GHz) and 5.5 dBi (at 5 GHz). The antenna has an average total radiation efficiency of over 50% (at 2.4 GHz), and at 5 GHz, greater than 45% performance.
Conclusion
The antenna has a great impact on the efficiency of wireless communication. Choosing a suitable antenna will greatly improve the devices connection efficiency. Molex’s Wi-Fi dual band antenna solution introduced in this article has the advantages of small size and high efficiency and will be one of the best product choices for relevant applications.