2.4. Rectangular patch antenna
Microstrip antenna is also called as a patch antenna. Microstrip patch antenna contains of a two sides. One side is a radiating patch of a dielectric substrate and the other side is the ground plane side as shown in Fig 2.2. Generally, patch antenna consists of materials that have good conducting properties such as Gold and Copper and it can be made any possible shape.
Figure 2.2: The simple design of rectangular patch antenna
However, in order to simplify analysis and performance predication. There are several shapes that can be used as the radiation patch antenna. The radiating patch may be square, rectangular, circular, elliptical, triangular, thin strip (dipole), and other common shapes shown in
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For Rectangular patch antenna, the length (L) of the patch is often (0.33330λ0< L < 0.50λ0), where (λ0) is the free space wavelength. The patch is chosen to be very thin such that (t<<λ0) (where (t) is the patch thickness). The height (h) of the dielectric substrate is usually defined (0.0030λ0 ≤ h ≤ 0.050 λ0). The dielectric constant of the substrate (Er) is normally in the range (2.20 ≤ Er ≤ 12).
Microstrip patch antennas radiate primarily because of the fringing fields between the patch edge and the ground plane. For good antenna performance, a thick dielectric substrate having a low dielectric constant is desirable since this provides better efficiency, larger bandwidth and better radiation [4]. However, such a configuration leads to a larger antenna size.
2.5: Antenna parameters
2.5.1 Radiation Pattern The power radiated or received by an antenna is a function of the angular position and radial distance from the antenna. The radiation pattern is good represented in the form of a three dimensional graph of power versus elevation and azimuth angles but more commonly represented by E-plane or H-plane where one angle is held fixed while the other is varied as shown in Figure
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Microstrip Antenna Feed Techniques
There are four popular techniques of feeding antenna which are microsrip line, coaxial probe, aperture coupling and proximity coupling. They are further divided into two main groups which are contacting (microstrip line and coaxial probe) and no contacting (aperture coupling and proximity coupling). For contacting method, the RF power is fed directly to the radiating patch while no contacting method an electromagnetic field coupling is done to transfer power between the microstrip line and the radiating patch [ ]
2.6.1 Microstrip line feeding Microstrip line feed is one of the easier methods to fabricate as it is a just conducing Strip connecting to the patch and therefore can be consider extension of patch. It is simple to Model and easy to match by controlling the inset position. However the disadvantage of this method is that as substrate thickness increases, surface wave and spurious feed radiation Increases which limit the bandwidth.
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Figure2.6: Microstrip Line
Patching holes by Andi Long is a creative nonfiction story about family relationships between her and her father. In this creative piece Long stressest that new relations can not be made if old relationships are still broken. A family cannot expect to build a new relationships if one person is still stuck on their past relationship. Long and her father had a weak father daughter relationship and she wanted to fix their bond. Her family hides that there family is broken by patching holes. Long later realized that sometimes you cannot fix a broken bond if one person isn 't ready for a new beginning. Throughout the narrative Long uses Idioms and symbols to describe her relationship with her family, and how there 's no hope in constructing stronger
The precedence of RFID is that it does not require direct contact or line-of-sight scanning. An RFID system consists of three components: an antenna and transceiver (often combined into one reader) and a transponder (the tag). The antenna uses radio frequency waves to transmit a signal that activates the transponder. When activated, the tag transmits data back to the antenna. The data is used to notify a programmable logic controller that an action should occur. The action could be as simple as raising an access gate or as complicated as interfacing with a database to carry out a monetary transaction. Low-frequency RFID systems (30 KHz to 500 KHz) have short transmission ranges (generally less than six feet). High-frequency RFID systems (850 MHz to 950 MHz and 2.4 GHz to 2.5 GHz) offer longer transmission ranges (more than 90 feet). In general, the higher the frequency, the more expensive the system. RFID is sometimes called dedicated short range communication (DSRC).
Radio Detection And Ranging (RADAR) “is a method of using radio waves to detect the existence of an object and then to find its position in relation to a known point, usually the site of the radar installation.” Radar technology can be used to detect the position, speed, and direction of the moving or stationary objects (“Pulse-modulated”). Radars, often used for “electromagnetic surveillance,” has various hardware and software parts that work together to produce an effective reading of the position and motion of the objects. The transmitter of the radar is used to initiate the process by amplifying the pulse signals. It has three parts: “a high powered amplifier (HPA) with a high-stability electron gun, waveform generator and timing, and an antenna” (Kolawole, 37). “The low energy signal, collected by the antenna, is brought through the circulator and the transmit...
The combination of the NFC antenna at the top of the iPhone 6 and the
The radio works because of sound waves being transmitted from one receptor to the next. Electrons moving through a wire create a magnetic field and when a second wire is placed next to the first the electrons are transmitted. The second wire is then able to turn the moving electrons into an electrical current which produces the same sound that created the moving electrons in the first wire (Gugliotta). Italian inventor, Gulielmo Marconi received the British patent for the radio in 1897. In 1901, Marconi discovered that radio wires did not have to be close to each other to work and that radio signals could be transmitted over very large distances. On December 13, 1901 Marconi successfully transmitted a radio wave 2,000 miles across the ocean from Poldhu, England to St. John’s, Newfoundland. U...
the area A of the loop or its orientation theta with respect to the field.
The level of RF a person receives is related to many factors, not only the placement of the antenna. Factors that can increase the level of RF are the number of “cells”, the distance to the “base station”, or the obstacles between the caller and the station. The number of cell zones depends on the user population. Heavily populated areas have more cells allowing for more telecommunication traffic. Being close to a cell site lowers the power needed to sustain a call, hence reduces the exposure to RF.
Wire time (or panghantar such as an antenna) conducts alternating current, electromagnetic radiation is propagated at the same frequency as the electric current. Depending on the situation, electromagnetic waves can be waves or like particles. As a wave, characterized by speed (speed of light), wavelength, and frequency. When considered as particles, they are known as photons, and each has an energy associated with the frequency of the waveform shown by the Planck relationship E = Hν, where E is the photon energy, h is the Planck constant - 6.626 × 10 -34 J · s - and ν is the frequency of the
Here is the information that goes a little deeper into the theory of how an antenna works. Although this is not a very intellectually intense site, I will warn those viewers on a lunch break or perhaps surfing the net while "between projects," that there are some concepts on this page that use what some people call "math," and other supposedly important "scientific information.
A small Bluetooth chip is inserted into a device, the chip replaces the cables and carries all the information normally carried by cables. Then the device transmits the information at a special frequency to a receiver Bluetooth chip via an antenna (made of copper wiring) attached on to the Bluetooth chip. The wave is produced by the movement of the electrons up and down in the antenna when data is transmitted from the master device. (Freeman, 2001) The Bluetooth chip and its antenna are shown in figure 1.
This range of radiation is Low Energy, Low Frequency and has Long Wavelength’s. Radio waves are utilised by antennae, they are used to transmit and receive data through modulation. This band contains the frequencies between 300Hz and 300GHz, or wavelengths longer than approximately one millimetre. This spectrum is typically regulated by the government, and licenses are sold to operators to utilise to reduce interference. This range of the spectrum is commonly used for Television, Amplitude Modulation Radio (AM Radio), Frequency Modulation Radio (FM Radio), mobile telecommunications and wireless networking.... ...
RADIO WAVES: Radio waves are used exactly for what it says — radio. They are also the waves responsible for the signals cell phones and televisions receive. Objects in space, such as planets and comets, giant clouds of gas and dust, and stars and galaxies, emit radio waves.