In radio engineering, an antenna or aerial is the interface between radio waves propagating through space and electric currents moving in metal conductors, used with a transmitter or receiver. In transmission, a radio transmitter supplies an electric current to the antenna's terminals, and the antenna radiates the energy from the current as electromagnetic waves (radio waves). In reception, an antenna intercepts some of the power of a radio wave in order to produce an electric current at its terminals, that is applied to a receiver to be amplified. Antennas are essential components of all radio equipment.
An antenna is an array of conductors (elements), electrically connected to the receiver or transmitter. Antennas can be designed to transmit and receive radio waves in all horizontal directions equally (omnidirectional antennas), or preferentially in a particular direction (directional, or high-gain, or “beam” antennas). An antenna may include components not connected to the transmitter, parabolic reflectors, horns, or parasitic elements, which serve to direct the radio waves into a beam or other desired radiation pattern.
The first antennas were built in 1888 by German physicist Heinrich Hertz in his pioneering experiments to prove the existence of waves predicted by the electromagnetic theory of James Clerk Maxwell. Hertz placed dipole antennas at the focal point of parabolic reflectors for both transmitting and receiving. Starting in 1895, Guglielmo Marconi began development of antennas practical for long-distance, wireless telegraphy, for which he received a Nobel Prize.
I am covering parabolic antennas with a school student in elementary physics, and I was looking for the specs of the (offset) antenna on her family's roof in order to calculate things like focal distance. She sent me a photo (she is on another continent), I found the brand specs, which lists it...
I have written a solver for my thesis which determines various parameters of a conical horn antenna for astronomy application. It is done with Mode Matching Technique (MMT) and some Rumsey's integrals for the aperture free space transitions. I have made some goal functions with the solver which...
I want to use small molecular - preferably CNT - "antennas" to produce THz signals to monitor activity in biological systems. After some googling, I've been reading things like "absorption spectra", "energy bands", "spectroscopy", as well as a bunch of antenna-science related jargon... I need...
This is the AN/APG-81 AESA Radar antenna by Northrop Grumman currently found in the F-35 (photo from wikipedia article).
It seems to have a very different structure than past AESA/PESA antennas. For example the APG-68 from the F-16 looks a lot like stacked, slotted wave guides to me.
Is it possible (and if so how practical) to overdamp a conductor wire that is many times longer than the wavelength of the incident radiation so that it doesn't reradiate any detectable amount, turning practically all incident radiation into heat?
I'm curious about anyone that has concrete hands on experience tinkering with very small low frequency antennas.
My band of interest is 6, 13 or 27 MHz.
I wonder if it is possible to design a very small physical antenna that will radiate with some directivity even if the efficiency is not so...
What i need are the ff:
basic guidelines on how to create an outdoor antenna (you can send links :))
the most suitable type of antenna that can receive 70 MHz tv station frequency. The antenna will be mounted less that 3 m from the ground.
computations that i need to know (you can also send...
I have created this thread especially for clearing some of the important concepts of Antenna and Designing Issues.
I have a question for all of you, related to Dipole Antenna.
I have designed a Folded Dipole Antenna resonating at center Frequency of 145.800MHz.
This antenna is...
Millimetre Wave Antennas for Gigabit Wireless Communications: A Practical Guide to Design and Analysis in a System Context
Huang, Kao‐Cheng ; Edwards, David J.
Chichester, UK: John Wiley & Sons, Ltd
But our library do not have this book. Has anyone know other book on this...
There are many webpage about dielectric antenna
But I cannot figure out where does the energy feed-in or take-out from the antenna?
My question stems from the Cosmic-1 satellites using single antennas for radio occultation and the cosmic-2 sats that will use a phased array antenna.
I've done a fair amount of research in regards to the phased array antenna. Overall it seems to improve the signal to noise ratio when making...
Hey guys, I am trying to design an Inductive Square Antenna Coil that will be milled onto my PCB. I am slightly confused when it comes to the matching circuit. To my understanding the matching circuit is there to have the same impedance value of the antenna, correct?
So my matching circuit...