EIRP allows calculation of real power output and field strength values, if actual antenna gain and transmitter output power are known. Dipole antennas are the most common type of antenna used and are omni-directional, propagating radio frequency RF energy degrees in the horizontal plane. These devices are constructed to be resonant at a half or quarter wavelength of the frequency being applied.
An antenna exhibits a typical impedance, allowing for matching of the antenna to the transmitter for maximum power transfer. If the antenna and transmitter are not matched, reflections will occur on the transmission line which will degrade the signal or even damage the transmitter.
These reflections are described by the term standing wave ratio SWR and indicate the efficiency of the transmission line. Directional and semi-directional antennas focus radiated power into narrow beams, adding a significant amount of gain in the process. Antenna properties are also reciprocal. The characteristics of a transmitting antenna, such as impedance and gain, are also applicable to a receiving antenna. This is why the same antenna can be used for both sending and receiving.
The gain of a highly directional parabolic antenna serves to amplify a weak signal; this is one reason why this type of antenna is frequently used for long distance links. A patch antenna is a semi-directional radiator using a flat metal strip mounted above a ground plane. Radiation from the back of the antenna is effectively cut off by the ground plane, enhancing forward directionality. This type of antenna is also known as a microstrip antenna.
It is typically rectangular and enclosed in a plastic enclosure. This type of antenna lends itself to being manufactured by standard printed circuit board methods. Patch antennas are widely used semi-directionals; a patch antenna can have a beamwidth of between 30 to degrees and a typical gain of 9 dB.
Sector antennas are another type of semi-directional antenna. Sector antennas provide a pie-shaped sector radiation pattern and are usually installed in what is known as a sectorized array.
Beamwidth for a sector antenna can be between 60 to degrees, with degrees being typical. In a sectorized array, antennas are mounted back-to-back to provide full degree coverage. Sector antennas are used extensively for cellular communication. A commonly used directional antenna is the Yagi-Uda Array, usually just called a Yagi. It was invented by Shintaro Uda and his colleague, Hidetsugu Yagi, in A Yagi antenna uses several elements to form a directional array.
A single driven element, typically a dipole, propagates RF energy; elements placed immediately in front of and behind the driven element re-radiate RF energy in phase and out of phase, enhancing and retarding the signal, respectively. What could take multiple guys 2 hours or more each to find is accessed in around 15 minutes on Experts Exchange.
All rights reserved. Covered by US Patent. Come for the solution, stay for everything else. Welcome to our community! What is the difference between a Patch antenna and a Yagi? They are both directional. Any advantage of one over the other? Yancey Landrum. Even I wanted to use a yagi antenna in a metro city, but was told that it requires some permission and if done without permissions it would be an offence.
Can someone using it throw some light on it? I think there is a restriction on the max amount of power on an unlicensed 2. Okay I will tell my experience. I build a Yagi-Uda antenna with 18 directors and it worked amazzingly well. I build for extending the range of my WiFi following tutorials on instructables and youtube.
So Yagi-Uda is a very cheap solution imho. If you need any help on that then quote me. Here's a pic. It's just a method of extending your home LAN So if you have a place some distance away from your primary home and intend to extend your home LAN to the other place.
Meant to say "half-duplex" right? Please enlighten me good sire! Since you getting into semantics, duplex could denote both half-duplex and full duplex For the discussion at hand, it is irrelevant Say you have an outhouse some distance away from your house - And there are days when you are supposed to sit there with nothing to do than just twiddling your thumb Now to kill time, you could browse the net or watch some movies lying on your home system But the outhouse is not close enough for you to run wires or for your wireless router signal to reach there Thats's where this kind of setup would come handy.
Omg so many replies, I was away for a personal work so couldn't look at replies. Because what you said is this And this is not a one way street- You are transmitting as well as receiving. Last edited: May 28, I meant that in a type of role being played by the antenna, not literally!
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