A report on Antenna (radio) and Loop antenna

A stack of "fishbone" and Yagi–Uda television antennas
A shortwave loop antenna
Animation of a half-wave dipole antenna radiating radio waves, showing the electric field lines. The antenna in the center is two vertical metal rods connected to a radio transmitter (not shown). The transmitter applies an alternating electric current to the rods, which charges them alternately positive (+) and negative (−). Loops of electric field leave the antenna and travel away at the speed of light; these are the radio waves. In this animation the action is shown slowed down enormously.
A quad antenna is a self-resonant loop in a square shape; this one also includes a parasitic element.
Electronic symbol for an antenna
Car roof-mounted 6 meter halo antenna for mobile amateur radio (WA8FJW). Note the triple-loop.
Antennas of the Atacama Large Millimeter/submillimeter Array.
Although a full 2.7 m in diameter, this receiving antenna is a "small" loop compared to LF and MF wavelengths.
An automobile's whip antenna, a common example of an omnidirectional antenna.
Small loop antenna used for receiving, consisting of about 10 turns around a 12 x rectangle.
Half-wave dipole antenna
Amount of atmospheric noise for LF, MF, and HF spectrum according CCIR 322
Diagram of the electric fields ( blue ) and magnetic fields ( red ) radiated by a dipole antenna ( black rods) during transmission.
The full wave loop (left) has maximum signal broadside to the wires with nulls off the sides, the small loop (right) has maximum signal in the plane of its wires with nulls broadside to the wires. (Pink and red represent "hot" or intense radiation; blue and indigo represent "cold" or low / no radiation.)
Cell phone base station antennas
Loop antenna, receiver, and accessories used in amateur radio direction finding at 80 m wavelength (3.5 MHz).
Standing waves on a half wave dipole driven at its resonant frequency. The waves are shown graphically by bars of color ( red for voltage, V and blue for current, I ) whose width is proportional to the amplitude of the quantity at that point on the antenna.
Ferrite loopstick antenna from an AM radio having two windings, one for long wave and one for medium wave (AM broadcast) reception. About 10 cm long. Ferrite antennas are usually enclosed inside the radio receiver.
Typical center-loaded mobile CB antenna with loading coil
A loop antenna for amateur radio under construction
Polar plots of the horizontal cross sections of a (virtual) Yagi-Uda-antenna. Outline connects points with 3 dB field power compared to an ISO emitter.
The wave reflected by earth can be considered as emitted by the image antenna.
The currents in an antenna appear as an image in opposite phase when reflected at grazing angles. This causes a phase reversal for waves emitted by a horizontally polarized antenna (center) but not for a vertically polarized antenna (left).
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A loop antenna is a radio antenna consisting of a loop or coil of wire, tubing, or other electrical conductor, that is usually fed by a balanced source or feeding a balanced load.

- Loop antenna

For non directional portable use, a short vertical antenna or small loop antenna works well, with the main design challenge being that of impedance matching.

- Antenna (radio)
A stack of "fishbone" and Yagi–Uda television antennas

3 related topics with Alpha

Overall

A common type of array antenna, a reflective array UHF television antenna. This example consists of eight dipole driven elements mounted in front of a wire screen reflector. The X-shaped dipoles give it a wide bandwidth to cover both the VHF (174–216 MHz) and UHF (470–700 MHz) TV bands. It has a gain of 5 dB VHF and 12 dB UHF and an 18 dB front-to-back ratio.

Antenna array

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A common type of array antenna, a reflective array UHF television antenna. This example consists of eight dipole driven elements mounted in front of a wire screen reflector. The X-shaped dipoles give it a wide bandwidth to cover both the VHF (174–216 MHz) and UHF (470–700 MHz) TV bands. It has a gain of 5 dB VHF and 12 dB UHF and an 18 dB front-to-back ratio.
Large planar array antenna of a VHF Russian mobile air defense radar, the Nebo-M. It consists of 175 folded dipole antennas. An early phased array, the antenna radiated a vertical fan-shaped beam which could be swept horizontally across the airspace in front of the antenna.
Animation showing how a phased array works.
A rooftop television antenna, an endfire parasitic array consisting of a combination of a Yagi and log periodic antenna
VHF collinear array of folded dipoles
Sector antennas (white bars) on cell phone tower. Collinear dipole arrays, radiating a flat, fan-shaped beam.
108 MHz reflective array antenna of an SCR-270 radar used during World War II consists of 32 half-wave dipole antennas in front of a reflecting screen.
US Air Force PAVE PAWS phased array 420 - 450 MHz radar antenna for ballistic missile detection, Alaska. The two circular arrays are each composed of 2677 crossed dipole antennas.
Some of the crossed-dipole elements in the PAVE PAWS phased array antenna, left
Batwing VHF television broadcasting antenna
Crossed-dipole FM radio broadcast antenna
Curtain array shortwave transmitting antenna, Austria. Wire dipoles suspended between towers
Turnstile antenna array used for satellite communication
Flat microstrip array antenna for satellite TV reception.
The Very Large Array, a radio telescope made of a Y-shaped array of 27 dish antennas in Socorro, New Mexico
HAARP, a phased array of 180 crossed dipoles in Alaska which can transmit a 3.6 MW beam of 3 - 10 MHz radio waves into the ionosphere for research purposes
Array of four helical antennas used as a satellite tracking antenna, Pleumeur-Bodou, France

An antenna array (or array antenna) is a set of multiple connected antennas which work together as a single antenna, to transmit or receive radio waves.

Quad antenna - This consists of multiple loop antennas in a line, with one driven loop and the others parasitic. Functions similarly to the Yagi antenna.

Radiation resistance

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Radiation resistance is that part of an antenna's feedpoint electrical resistance that is caused by the emission of radio waves from the antenna.

Small receiving antennas, such as the ferrite loopstick antennas used in AM radios, also have low radiation resistance, and thus produce very low output.

A stack of ferrite magnets

Ferrite (magnet)

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Ceramic material made by mixing and firing large proportions of iron oxide (Fe2O3, rust) blended with small proportions of one or more additional metallic elements, such as strontium, barium, manganese, nickel, and zinc.

Ceramic material made by mixing and firing large proportions of iron oxide (Fe2O3, rust) blended with small proportions of one or more additional metallic elements, such as strontium, barium, manganese, nickel, and zinc.

A stack of ferrite magnets
Various ferrite cores used to make small transformers and inductors

They are used in the electronics industry to make efficient magnetic cores called ferrite cores for high-frequency inductors, transformers and antennas, and in various microwave components.

Because of their comparatively low losses at high frequencies, they are extensively used in the cores of RF transformers and inductors in applications such as switched-mode power supplies and loopstick antennas used in AM radios.