Antenna design Definition and 22 Discussions

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.

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  1. Narayanan KR

    Resonant Frequency for a Coil-Only Antenna

  2. nomadreid

    TV antenna dish: depth, f/D, or focal distance

    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...
  3. tworitdash

    A Maximum reception/transmission criteria for Conical Horn Antennas

    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...
  4. qnach

    Performance of a complimentary antenna?

    Suppose the performance of an antenna is calculated. How about its complimentary antenna?
  5. qnach

    Connection between relative permittivity and bandwidth

    What is the connection of relative permittivity and bandwidth of an antenna? Higher relative permittivity resulted in high wider bandwidth?
  6. P

    THz Radiation, Antennas: Need background knowledge

    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...
  7. R

    Help Identifying AESA Antenna Structure Type found in the F-35 aircraft

    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. So...
  8. C

    Is it possible to make a passive element that doesn't reemit EM

    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?
  9. T

    Can a radio frequency be lowered by a passive circuit?

    Is it possible to design an unpowered antenna, (possibly some kind of RLC circuit) which will receive a radio wave at a particular frequency and then re-emit it at a lower frequency?
  10. qnach

    Antenna of this shape? What is the benefit?

    Is there a (dielectric) antenna of this shape ---o---o---o---o--- | | | | ---o---o---o---o--- i.e. a ladder? What is the good for such antennas?
  11. D

    *Very* Small Low Freq Antennas with directivity?

    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...
  12. maearnie

    Outdoor antenna design

    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...
  13. qnach

    Reasons for choosing square antenna?

    Is there any particular reason to choose a square shape antenna like instead of a circular shape?
  14. Shubham Jaydeokar

    How to test a simple Dipole Antenna on Spectrum Analyser?

    Hello Experts, 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...
  15. qnach

    Small loop antenna

    Is a small-loop antenna a dipole or a monopole? Is a (small) 8-shape antenna a dipole or a monopole? Is a 8-shape antenna a dipole antenna?
  16. qnach

    S-shape and 8-shape Antennae

    Over the literatures there are S-shape and 8-shape antennae been discussed. What are the differences? The 8-shape seems to be found in amature using magnetic loop. Why magnetic?
  17. qnach

    Is there an antenna with this shape?

    Is there an antenna of S shape or perhaps a butterfly shape? What is the benefit of such design?
  18. qnach

    Books on dielectric antennae

    WiKi indicate 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...
  19. qnach

    Dielectric antennae

    There are many webpage about dielectric antenna For instance, But I cannot figure out where does the energy feed-in or take-out from the antenna?
  20. qnach

    I Non-conductor made antenna?

    Could an antenna made from a non-conductor or a poor conductor?
  21. Tone L

    Phased array antenna vs single antenna for remote sensing.

    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...
  22. A

    Inductance of Square Coil Antenna on PCB

    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...