RFID ANTENNA DESIGN
Our antenna design works are done by our electrical electronics engineers within the scope of our company. In ETSI (European Telecommunications Standards Institute) standards, we are producing high gain antennas for UHF RFID systems defined in the 865-867 MHz frequency range.
We try to increase the reading area, gain bandwidth according to the existing systems. Thanks to our antenna designs, which are low production cost easy to manufacture, we eliminate dependency to abroad.
Demo Antenna Design
We make alternative antenna designs to the examples of international markets by making totally domestic design production.
It has been observed that our measurements are much more efficient than the alternatives of our antennas that we have implemented in our company at the Antenna Laboratory of Dokuz Eylül University.
Below are some of our studies information about measurement results.
Demo Antenna Measurement Results
Antenna is a system consisting of a conductor conductors that converts electrical energy into electromagnetic interference (transmitting antenna) converts electromagnetic energy into electrical energy (receiving antenna). The sending receiving characteristics of an antenna are the same. This is called reciprocity of antennas. In two-way communication, the same antenna is used in both send receive.
Performance Parameters of Antennas
1. Radiation pattern
The radiation pattern is a graph showing the angular variation of the antenna strength (the intensity of the electromagnetic field) at a constant distance in the far field of the antenna. The antenna radiation pattern is three-dimensional, but in practice, it is usually drawn as two-dimensional cross-sections in horizontal vertical planes. When working as an antenna receiver transmitter, the radiation pattern is the same. The size of the radiation pattern does not matter. What matters is the relative distance from the antenna position to the points forming the radiation pattern. The radiation pattern of an antenna is obtained by measuring the intensity of the electromagnetic field in the far-field region of the antenna. The area near the antenna any radiating element is defined as the near field, while the far field is defined as the far field. The near field is the area the electric magnetic field components do not show the plane wave character. The far field is the region plane wave approach can be done. The definitions of the near far fields are determined by parameters such as frequency, antenna dimensions, antenna type interactivity. The power density is measured in the far field E field (electric field) sensor H field (magnetic field) sensor. It is difficult to measure the power density in the near field. Communication is achieved by using the far field component of the antennas. The simplest radiation pattern is the radiation pattern of an isotropic antenna, which is defined as a theoretical antenna (not implemented in practice). The radiation pattern of the isotropic antenna is a beam with an isotropic antenna at its center. In the radiation pattern of the antenna, there are 3 different radiation types as main lobe, back lobe side lobes.
The direction of the antenna is the ratio of the power density at the far end of the antenna to the maximum power at which the same power isotropic antenna is at the same distance.
Beam is the direction the antenna sends receives maximum power from. The beamwidth of a directional antenna is the angle between the directions in which the maximum radiant power falls on the beam in the beam diagram. In these directions, the power falls halfway, the power level is 3 dB below maximum power. The beamwidth is given in terms of half power beamwidth 3-dB beamwidth.
Antenna efficiency is related to the spreading of the power applied to the antenna by the antenna the expenditure within the antenna. Also known as radiation efficiency, is the ratio of the electrical power applied to the antenna to the radiated power of the antenna. If this power applied to an antenna input can radiate away is called a high efficiency antenna; a low efficiency antenna does not spread away but absorbs a large of it. Antenna efficiency varies with the selection of the antenna transmission line for incompatible impedance values. In short, antenna efficiency is a measure of antenna losses is between 0 1.
Antenna gain is equal to antenna efficiency multiplied by directionality. The gain of a lossless antenna is equal to the gain of the antenna. Antenna gain is commonly given in dB. It can also be expressed in terms of dBi to indicate that it is relative to the isotropic antenna. Antenna gain is the directing of the antenna output power in a certain direction rather than obtaining a larger output power than the power applied to the antenna. That is, the radiation power is reduced to some direction, it is replicated in one direction.
The polarization of the antenna is named according to the type of the electric field vector that is emitted from the antenna. There are three types of antenna polarizations, linear, circular elliptical. Linear polarization; If the electric field is horizontal, it is called horizontal polarization. If the electric field is vertical, it is called vertical polarization. Circular polarization is called right-hand left-hand polarized according to the direction of rotation of the electromagnetic waveguide the circular rotation of the vector of the electric field. The elliptic polarization is called the right-hand left-hand polarized according to the orientation of the electromagnetic wave the direction in which the electric field vector is drawn by ellipsis. Nonconsequential to the polarity, the electric magnetic field vectors are perpendicular to each other are located in a plane perpendicular to the direction of propagation of the electromagnetic waveguide. This is called a plane wave. These two vectors, rotating perpendicular to each other at a certain angular velocity, form an electromagnetic field traveling in the direction of travel of a screw relative to the direction of rotation of the electric field vector.
The input impedance of the antenna is the flux rate of the voltage at the feed ends of the antenna. In order to minimize the losses on the antenna resistance thus increase the antenna efficiency, the characteristic impedance of the transmission line feeding the antenna must be chosen as the conjugate of the antenna impedance. This process is called impedance matching.
The bandwidth of the antenna is the frequency range in which the antenna’s significant performance parameters are within acceptable limits. In general, the bandwidth of the antenna is considered to be between the points the s-parameters reach -10 dB.
The ability to scan the antenna is the ability to move the main beam on the radiation pattern. Moving the main beam can be done electrically by rotating the antenna mechanically by holding the antenna steady changing the phases of the currents applied to the multiple antenna elements creating delays. Antennas that can scan electrically are called phased-array antennas. The multiple radiation elements of the phased array antennas can be composed of dipoles, pen-ended waveguides, twisted waveguides, microstrip antennas other types of antennas. Phase array antennas are used in radar, direction finding systems varying traffic conditions that require adjustment of the beam yell. In three-dimensional scanning systems, mechanical scanning in one plane electronic scanning in the perpendicular plane can be performed.
Band Frequency Wavelength
VLF – Very Low Frequency 3KHz – 30KHZ / 100 km – 10 km
LF – Low Frequency 30KHz – 300KHz / 10 km – 1 km
MF – Medium Frequency 300KHz – 3MHz / 1km – 100m
HF – High Frequency 3MHz – 30 MHz / 100m – 10m
VHF – Very High Frequency 30MHz – 300MHz / 10m – 1m
UHF – Ultra High Frequency 300MHz – 3GHz / 1m – 10cm
SHF – Super High Frequency 3GHz – 30 GHz / 10 cm – 1 cm
EHF – Extremely High Frequency 30GHz – 300 GHz / 1cm – 1mm
In the direction of the specified performance parameters frequency ranges, our company continues to work on RFID antennas in UHF (ultra high frequency) band, that is 300Mhz – 3Ghz range. Efforts are being made to improve the reading range, gain bandwidth according to existing systems.