A discone antenna is a version of a
biconical antenna
In radio systems, a biconical antenna is a broad-bandwidth antenna made of two roughly conical conductive objects, nearly touching at their points.Zhuohui Zhang,''Analysis and design of a broadband antenna for software defined radio'', ProQuest, 2 ...
in which one of the cones is replaced by a disc. It is usually mounted vertically, with the disc at the top and the cone beneath.
Omnidirectional
Omnidirectional refers to the notion of existing in every direction. Omnidirectional devices include:
* Omnidirectional antenna, an antenna that radiates equally in all directions
* VHF omnidirectional range, a type of radio navigation system for ...
, vertically
polarized and with
gain
Gain or GAIN may refer to:
Science and technology
* Gain (electronics), an electronics and signal processing term
* Antenna gain
* Gain (laser), the amplification involved in laser emission
* Gain (projection screens)
* Information gain in d ...
similar to a
dipole
In physics, a dipole () is an electromagnetic phenomenon which occurs in two ways:
*An electric dipole deals with the separation of the positive and negative electric charges found in any electromagnetic system. A simple example of this system ...
, it is exceptionally
wideband
In communications, a system is wideband when the message bandwidth significantly exceeds the coherence bandwidth of the channel. Some communication links have such a high data rate that they are forced to use a wide bandwidth; other links may h ...
, offering a frequency range ratio of up to approximately 10:1. The
radiation pattern
In the field of antenna design the term radiation pattern (or antenna pattern or far-field pattern) refers to the ''directional'' (angular) dependence of the strength of the radio waves from the antenna or other source.Constantine A. Balanis: � ...
in the
vertical plane
In astronomy, geography, and related sciences and contexts, a '' direction'' or '' plane'' passing by a given point is said to be vertical if it contains the local gravity direction at that point.
Conversely, a direction or plane is said to be h ...
is quite narrow, making its
sensitivity
Sensitivity may refer to:
Science and technology Natural sciences
* Sensitivity (physiology), the ability of an organism or organ to respond to external stimuli
** Sensory processing sensitivity in humans
* Sensitivity and specificity, statisti ...
highest in the direction of the
horizon
The horizon is the apparent line that separates the surface of a celestial body from its sky when viewed from the perspective of an observer on or near the surface of the relevant body. This line divides all viewing directions based on whether ...
and rather less for signals coming from relatively close by.
History
On February 6, 1945,
Armig G. Kandoian of
New York City
New York, often called New York City or NYC, is the most populous city in the United States. With a 2020 population of 8,804,190 distributed over , New York City is also the most densely populated major city in the U ...
was awarded
U.S. patent
Under United States law, a patent is a right granted to the inventor of a (1) process, machine, article of manufacture, or composition of matter, (2) that is new, useful, and non-obvious. A patent is the right to exclude others, for a limite ...
number (assignor to Federal Telephone and Radio Corporation, later merged with
ITT Corporation
ITT Inc., formerly ITT Corporation, is an American worldwide manufacturing company based in Stamford, Connecticut. The company produces specialty components for the aerospace, transportation, energy and industrial markets. ITT's three businesse ...
), from an application made on May 15, 1943.
Excerpt from the Kandoian patent:
In keeping with progress made during the last few years in the development of ultra-high frequency
Ultra high frequency (UHF) is the ITU designation for radio frequencies in the range between 300 megahertz (MHz) and 3 gigahertz (GHz), also known as the decimetre band as the wavelengths range from one meter to one tenth of a meter ...
radio
Radio is the technology of signaling and communicating using radio waves. Radio waves are electromagnetic waves of frequency between 30 hertz (Hz) and 300 gigahertz (GHz). They are generated by an electronic device called a transm ...
technique, and applications thereof to aircraft
An aircraft is a vehicle that is able to fly by gaining support from the air. It counters the force of gravity by using either static lift or by using the dynamic lift of an airfoil, or in a few cases the downward thrust from jet engines. ...
communication, direction finding
Direction finding (DF), or radio direction finding (RDF), isin accordance with International Telecommunication Union (ITU)defined as radio location that uses the reception of radio waves to determine the direction in which a radio stat ...
, and so forth, it has become necessary to develop special antennas and antenna systems suitable for installation on such aircraft. Flying conditions are such that these antennas must necessarily be small and rigid in their construction and also offer a minimum of wind resistance
In fluid dynamics, drag (sometimes called air resistance, a type of friction, or fluid resistance, another type of friction or fluid friction) is a force acting opposite to the relative motion of any object moving with respect to a surrounding flu ...
, in order that the flying efficiency of the aircraft will be unimpaired. In accordance with my invention I have provided a small rigid antenna suitable for mounting on the surface of the fuselage
The fuselage (; from the French ''fuselé'' "spindle-shaped") is an aircraft's main body section. It holds crew, passengers, or cargo. In single-engine aircraft, it will usually contain an engine as well, although in some amphibious aircraft t ...
or other component of the airplane structure and in certain embodiments I have also provided a streamlined protecting shield or housing covering or so cooperating with the construction of the antenna system as to greatly reduce wind resistance.
Description

The discone antenna has a useful frequency range of at least 10 to 1.
When employed as a transmitting antenna, it is often less efficient than an antenna designed for a more limited frequency range. SWR (
standing wave ratio
In radio engineering and telecommunications, standing wave ratio (SWR) is a measure of impedance matching of loads to the characteristic impedance of a transmission line or waveguide. Impedance mismatches result in standing waves along the tra ...
) is typically 1.5:1 or less over several octaves of frequency.
A discone antenna consists of three main parts: the disc, the cone, and the insulator.
* The disc: The disc should have an overall diameter of 0.7 times a quarter
wavelength
In physics, the wavelength is the spatial period of a periodic wave—the distance over which the wave's shape repeats.
It is the distance between consecutive corresponding points of the same phase on the wave, such as two adjacent crests, tr ...
of the antenna's lowest
frequency
Frequency is the number of occurrences of a repeating event per unit of time. It is also occasionally referred to as ''temporal frequency'' for clarity, and is distinct from '' angular frequency''. Frequency is measured in hertz (Hz) which is ...
. The antenna's feed point is at the center of the disc. It is usually fed with 50-ohm
coaxial cable
Coaxial cable, or coax (pronounced ) is a type of electrical cable consisting of an inner conductor surrounded by a concentric conducting shield, with the two separated by a dielectric ( insulating material); many coaxial cables also have a ...
, with the center conductor connected to the disc, and the outer conductor to the cone.
* The cone: The length of the cone should be a quarter wavelength of the antenna's lowest operating frequency.
The cone angle is generally from 25 to 40 degrees.
* The insulator: The disc and cone must be separated by an insulator, the dimensions of which determine some of the antenna's properties, especially on near its high frequency limit.
Construction materials
A discone may be made from solid metal sheet (often
copper
Copper is a chemical element with the symbol Cu (from la, cuprum) and atomic number 29. It is a soft, malleable, and ductile metal with very high thermal and electrical conductivity. A freshly exposed surface of pure copper has a pinkish ...
), which is practical for small indoor UHF antennas, such as for
Wi-Fi
Wi-Fi () is a family of wireless network protocols, based on the IEEE 802.11 family of standards, which are commonly used for local area networking of devices and Internet access, allowing nearby digital devices to exchange data by radio w ...
.
At lower frequencies a sufficient number of metal wires or rods in a
spoke
A spoke is one of some number of rods radiating from the center of a wheel (the hub where the axle connects), connecting the hub with the round traction surface.
The term originally referred to portions of a log that had been riven (split l ...
configuration is often used to approximate a solid surface. This simplifies construction and reduces wind loading.
The spokes may be made of stiff wire, brazing rods or even
coat hanger wire.
The optimal number of rods comprising the disc and cone is often quoted as being from 8 to 16.
Applications
The discone's wideband coverage makes it attractive in commercial, military,
amateur radio
Amateur radio, also known as ham radio, is the use of the radio frequency spectrum for purposes of non-commercial exchange of messages, wireless experimentation, self-training, private recreation, radiosport, contesting, and emergency communi ...
and
radio scanner
A scanner (also referred to as a radio scanner) is a radio receiver that can automatically tune, or ''scan'', two or more discrete frequencies, stopping when it finds a signal on one of them and then continuing to scan other frequencies when the ...
applications.
The discone's inherently wideband nature permits it to broadcast undesirable
spurious emission
In radio communication, a spurious emission is any component of a radiated radio frequency signal the complete suppression of which would not impair the integrity of the modulation type or the information being transmitted. A radiated signal out ...
s from faulty or improperly filtered
transmitter
In electronics and telecommunications, a radio transmitter or just transmitter is an electronic device which produces radio waves with an antenna. The transmitter itself generates a radio frequency alternating current, which is applied to ...
s.
Extending low-frequency response
A vertical whip may be affixed to the center of the disc in order to extend the low frequency response, but this may compromise efficiency at higher frequencies. In this configuration, at lower frequencies the discone may more closely resemble a
ground plane antenna
A whip antenna is an antenna consisting of a straight flexible wire or rod. The bottom end of the whip is connected to the radio receiver or transmitter. A whip antenna is a form of monopole antenna. The antenna is designed to be flexible so t ...
or a
coaxial dipole.
See also
*
Antenna
Antenna ( antennas or antennae) may refer to:
Science and engineering
* Antenna (radio), also known as an aerial, a transducer designed to transmit or receive electromagnetic (e.g., TV or radio) waves
* Antennae Galaxies, the name of two collid ...
*
Antenna types
In radio systems, many different antenna types are used whose properties are especially crafted for particular applications. Antennas can be classified in various ways. The list below groups together antennas under common operating principles, foll ...
*
Biconical antenna
In radio systems, a biconical antenna is a broad-bandwidth antenna made of two roughly conical conductive objects, nearly touching at their points.Zhuohui Zhang,''Analysis and design of a broadband antenna for software defined radio'', ProQuest, 2 ...
*
Very high frequency
Very high frequency (VHF) is the ITU designation for the range of radio frequency electromagnetic waves ( radio waves) from 30 to 300 megahertz (MHz), with corresponding wavelengths of ten meters to one meter.
Frequencies immediately below V ...
*
Ultra high frequency
Ultra high frequency (UHF) is the ITU designation for radio frequencies in the range between 300 megahertz (MHz) and 3 gigahertz (GHz), also known as the decimetre band as the wavelengths range from one meter to one tenth of a meter ...
*
Radio scanner
A scanner (also referred to as a radio scanner) is a radio receiver that can automatically tune, or ''scan'', two or more discrete frequencies, stopping when it finds a signal on one of them and then continuing to scan other frequencies when the ...
*
Amateur radio
Amateur radio, also known as ham radio, is the use of the radio frequency spectrum for purposes of non-commercial exchange of messages, wireless experimentation, self-training, private recreation, radiosport, contesting, and emergency communi ...
References
External links
UHF Discone AntennaParabolic Discone (Michael Lake KD8CIK)Broadband radial discone antenna: Design, application and measurementsDiscone antenna basics
{{Antenna Types
Radio frequency antenna types
Antennas (radio)