Do you know what are the most basic terms in the world of antenna technology?
Active and passive antenna
We divide antennas into active and passive. The difference between an active and a passive antenna is that the active antenna includes an integrated amplifier that amplifies the signal level. Active antennas can be used for both reception and transmission and need to be powered. Nominal power values are around 2.2-5 V. GNSS antennas are a common example of active antennas. The passive antenna is without an amplifier. In our article we will help you choose the right antenna.
Types of cables and connectors
The choice of cable and connector types is essential for an antenna to function properly. The connector serves as mechanical connection between the antenna and the RF system. The cable is used for direct connection of the HF transmission line signal. The choice of a quality cable and connector helps the resulting efficiency of the entire antenna system.
Antenna attachment methods
We offer a wide range of attachment methods: adhesive, mounting, screw, magnetic and soldering.
Frequency band means a continuous range of frequencies, defined by a lower and upper cut-off frequency. The difference between the two cutoff frequencies is called the bandwidth.
The signal level is given in dBm and represents the ratio of the current signal level to the 1mW reference value. The basis of wireless information transmission is an antenna, which is used to receive and transmit a radio signal. The antenna must be chosen appropriately so that it meets the requirements of the installation and has the required properties. Needless to mention a saying is used in antenna technology, the best amplifier is the antenna itselr. The use of preamplifiers can cause other problems.
Attenuation (loss) is a decrease in signal strength. It is given in decibels (dB). Attenuation is undesirable, it is often caused by mismatch of the RF transmission system. These losses can be caused by impedance, polarization mismatch or it can also be inserted attenuation eg on coaxial cable (which increases in proportion to cable length), connectors and splitters.
A complex resistance on alternating current, which is composed of two components of real resistance R and imaginary or reactive reactance X. The unit of impedance is ohm Ω, usually denoted by a capital letter Z. The most common antenna impedance is either 50 or 75 Ω.
The VSWR parameter is a ratio that numerically expresses the degree of impedance matching of the input terminals of the antenna to the line (hereinafter transmitter and receiver) to which it is connected. Usually, an impedance value of 50 Ohm is calculated. In order to maintain the most efficient transmission of energy through the antenna, the ratio must be close to 1: 1. If the antenna is not adjusted, energy is reflected. The reflected waves can then create standing waves. This causes attenuation by impedance mismatch, further overheating, in the worst case scenario, damage to the transmitting / receiving part.
S11 or input reflection factor is the designation of the ratio of the power of the reflected and successive waves, given in dB. This would not result in energy reflections, but in efficient transmission. The value of the reflected energy from the input terminals of the antenna is expressed in dB and is shown in negative values - ideally as negative as possible. The ideal antenna should have an S11 value of infinity → the antenna would be ideally impedance matched. VSWR 1: 1.
Gain is one of the most important parameters of the antenna and characterizes its efficiency. Gain indicates an increase in signal strength and is closely related to its directivity. The antenna is a passive element and its gain is achievable (unlike, for example, the gain of the amplifier) solely at the expense of increasing its directivity. It is measured in dBi and dBd depending on the measurement method used.
The efficiency of the antenna is expressed as the ratio of the power radiated by the antenna Pv to the delivered power Pz. The resulting value is then given in%.
Omnidirectional and directional antenna
The directionality of the antenna is presented by a directional (radiation) diagram. The radiation diagram is really three-dimensional, but in practice it is represented in most cases by a 2D spatial section in the vertical or horizontal plane. From this diagram, a very important parameter called the antenna radiation angle is determined. It is the angle of the radiation maximum, which is defined by two values, which correspond to a decrease of the maximum field strength by 3 dB.
Polarization is divided into horizontal or vertical and is selected according to the received transmitter. It describes the position of the transmitting or receiving antenna elements perpendicular to the direction of signal propagation. With horizontal polarization, the antenna elements are placed horizontally. Vertical polarization indicates vertical orientation. Horizontal polarization is used in most parts of the Czech Republic. Vertical polarization is used in densely populated areas - it can more easily deal with difficult terrain.
GPS technology is the most accurate navigation system that allows you to determine the exact position on the map using an electronic receiver connected to the antenna. GPS location allows the use of navigation, tracking devices or logbooks in cars.
GSM This is a cellular network to which mobile phones connect via the nearest cell. GSM operates on several radio frequencies. The GSM Group has designed a system that uses 2nd generation (2G) digital technology, thanks to which it is possible to make telephone calls, send short SMS text messages and data transmissions. Using a SIM card makes it easy to change your mobile phone.
WiFi networks are today's standard - they use the 2.4 and 5 GHz bands. WiFi technology is used for local connection of devices (LAN) and also mainly for internet connection. WiFi networks are primarily intended for households, antennas should be designed to transmit signals well from routers and modems towards the devices that connect to this network.
5G technology will gradually replace or expand today's very popular LTE networks. It is characterized by a higher baud rate and a significant reduction in response time. 5G antennas are used in M2M, IoT devices and IoT systems.
GNSS (Global Navigation Satellite System) is a designation for satellite systems that are used to pinpoint geographical location. The GLONASS system uses two signals: the Russian Federation operates a system called the Global Orbiting Navigation Satellite System (GLONASS) and the United States operates a system called the Global Positioning System (GPS).
The full name of the abbreviation LTE is Long Term Evolution. LTE technology builds on the current 3G (UMTS) network and brings several improvements. LTE is the so-called fast internet for communication for mobile devices and data terminals. LTE is based on GSM / EDGE and UMTS / HSPA networks. In the Czech Republic, three frequencies 800, 900 and 1800 MHz are used for LTE.