Decreasing the permittivity also increases the antenna's bandwidth. The efficiency is also increased with a lower value for the permittivity. The impedance of the antenna increases with higher permittivities. Higher values of permittivity allow a "shrinking" of the patch antenna. Particularly in cell phones, the designers are given very little space and want the antenna to be a half-wavelength long.
Instead, some of the power is reflected back. The signal when transmitted or received is done over a range of frequencies. This particular range of frequencies is allotted to a particular signal, so that other signals may not interfere in its transmission. The particular frequency within a frequency band, at which the signal strength is maximum, is called the resonant frequency. It is also called as centre frequency fC of the band. The Percentage bandwidth is calculated to know how much frequency variation either a component or a system can handle.
Radiation emitted from an antenna that is more intense in a particular direction indicates the maximum intensity of that antenna. The emission of radiation to a maximum possible extent is nothing but radiation intensity. Radiation Intensity is obtained by multiplying the power radiated with the square of the radial distance.
The above equation denotes the radiation intensity of an antenna. Wireless communication is done in the form of waves. Hence, we need to look at the properties of waves in communications. In this paper, we are going to learn the basic concepts of antennas, specifications and different types of antennas.
They are many types of antennas depending upon. In telecommunication, a microstrip antenna also known as a printed antenna usually means an antenna fabricated using microstrip techniques on a printed circuit board PCB.
It is a kind of internal antenna. They are mostly used at microwave frequencies. An individual microstrip antenna consists of a patch of metal foil of various shapes a patch antenna on the surface of a PCB printed circuit board , with a metal foil ground plane on the other side of the board.
Most microstrip antennas consist of multiple patches in a two-dimensional array. The antenna is usually connected to the transmitter or receiver through foil microstrip transmission lines. The radiofrequency current is applied or in receiving antennas the received signal is produced between the antenna and ground plane.
Microstrip antennas have become very popular in recent decades due to their thin planar profile which can be incorporated into the surfaces of consumer products, aircraft and missiles; their ease of fabrication using printed circuit techniques; the ease of integrating the antenna on the same board with the rest of the circuit, and the possibility of adding active devices such as microwave integrated circuits to the antenna itself to make active antennas.
The most commonly employed microstrip antenna is a rectangular patch that looks like a truncated microstrip transmission line. It is approximately one-half wavelength long. When air is used as the dielectric substrate, the length of the rectangular microstrip antenna is approximately one-half of a free-space wavelength.
As the antenna is loaded with a dielectric as its substrate, the length of the antenna decreases as the relative dielectric constant of the substrate increases. An early model of the microstrip antenna is a section of microstrip transmission line with equivalent loads on either end to represent the radiation loss. The patch antennas may be powered by many methods. The most famous feeding techniques employed in the microstrip patch antenna are coaxial probe, feeding technique with microstrip line and aperture or proximity coupling methods.
In this kind of feeding process Fig. This feeding method offers the benefit that the conducting line can have the opportunity of being engraved on the same substrate of patch antenna providing a planar shape. The width of conducting element is smaller as compared to the patch antenna. The outside conductor of a coaxial connector is attached at the ground plane, while the inside is extended across the dielectric and is welded at the radiating element antenna. Figure 3 show this type of feed technique.
Coaxial Probe Feed. This feeding technique Fig. In this type of feed technique, a microstrip feed line is separated by the ground plane to the radiating patch. The feed line and the radiating element is coupled through an aperture or a slot in the ground plane. The variations in the coupling will depend on the width and length of the slot to improve the simulation result of bandwidths and return losses. The slot is usually centred under the radiating element. Electromagnetic field solvers for applications across the EM spectrum are contained within a single user interface in CST Studio Suite.
The solvers can be coupled to perform hybrid simulations, giving engineers the flexibility to analyze whole systems made up of multiple components in an efficient and straightforward way. CST Studio Suite is used in leading technology and engineering companies around the world. It offers a considerable product to market advantages, facilitating shorter development cycles and reduced costs.
Here are the basic shapes of the patch shown in Fig- ure 7. This antenna has resonated at 3. The bandwidth of the antenna is Return loss of the antenna is This antenna can be used in wireless applications. Khushboo Naruka et. In this antenna, FR4 is used as a dielectric substrate material and copper as a patch material. The antenna resonates at 4. The coaxial probe feed is used to feed the antenna. It is as shown below in the Figure 9. Raju Verma et. It is as shown below in Figure 8.
Srivastava et. It is as shown below in Figure In this design, they have used Glass Epoxy as substrate material and copper as a patch material. The antenna resonates at 1. The bandwidth of it is Shobhit K. Patel et. It is as shown in Figure In this design, they have used FR4 epoxy as substrate material and copper as patch material. Further, a microstrip patch antenna was fabricated using the dimensions of the simulated antenna.
The antenna parameters were compared between simulation results and experimental results and the antenna was qualified for use in L-band frequency range with minimum return loss and maximum bandwidth. A microstrip patch antenna consists of a radiating patch on one side of a dielectric substrate and a ground plane on the other side [6]. DOI: Basic Structure of Microstrip Patch Antenna Due to the fringing effects, the patch of the microstrip antenna looks greater than its physical dimensions as shown in Fig.
Figure 2. Physical and effective lengths of Rectangular Microstrip patch Antenna The length and width of the patch determines the characteristics of the antenna. The dimensions of a microstrip patch antenna depend on the resonant frequency and value of the dielectric constant. The micro strip patch structures are relatively easy to manufacture and have turned micro strip analysis into an extensive research problem.
Research on micro strip antenna in the 21st century aimed at size reduction, increasing gain, wide bandwidth, multiple functionality and system-level integration. With the wide spread proliferation of wireless communication technology in recent years, the demand for compact, low profile and broadband antennas has increased significantly. To meet the requirement, the micro strip patch antenna have been proposed because of its low profile, light weight and low cost.
Common micro strip antenna shapes are square, rectangular, circular and elliptical, but any continuous shape is possible. There are several techniques available to feed or transmit Electromagnetic energy to a micro strip patch antenna. The feeding techniques used in the micro strip antenna are divided into two important classes as given below:- Contacting Feed: - In this method, the patch is directly fed with RF power using the contacting element such as micro strip line or coaxial line.
Non-Contacting Feed: - In this method, the patch is not directly fed with the RF power but instead power is transferred to the path from the feed line through electromagnetic coupling. The most commonly used non- contacting feed methods are Aperture Coupled feed and Proximity Coupled Feed.
The role of feeding is very important in case of efficient Operation of antenna to improve the antenna input Impedance matching. Microstrip Line Feed 2. Inset Feed 3. Co-axial Feed 4. Aperture Coupled Feed 5. Proximity Coupled Feed A.
Microstrip line Feed:- In this type of feed technique, a conducting strip is connected directly to the edge of the Microstrip patch. The conducting strip is smaller in width as compared to the patch and this kind of feed arrangement has the advantage that the feed can be etched on the same substrate to provide a planar structure.
0コメント