| |
HB9ABX > TECHNIK 06.06.20 14:35l 110 Lines 5994 Bytes #999 (999) @ WW
BID : 66UDB0FHN04H
Read: GUEST
Subj: Antennas an Physics
Path: IW8PGT<IZ3LSV<DB0ERF<DB0RES<DB0OVN<DB0GOS<DB0RBS<OE5XBL<OE2XZR<DB0FHN
Sent: 200606/1211z @:DB0FHN.#BAY.DEU.EU [JN59NK Nuernberg] obcm1.07b12 LT:999
From: HB9ABX @ DB0FHN.#BAY.DEU.EU (Felix)
To: TECHNIK @ WW
Reply-To: HB9ABX @ HB9EAS.CHE.EU
X-Info: Sent with login password
Antennas and Physics
Antennas are structures, which convert electrical oscillations of a line into
radio waves inspace, and respectively convert radio waves into electrical
oscillations in a line.
In classical theory, an antenna is treated as a device, where an oscillating
current flowing in a conductor produces a (electro) magnetic field (EM field),
which converges into E and H field, to an electromagnetic wave (EM wave)
travelling in space. The exact cause of the EM wave is said to be acceleration
of electric charge.
(See http://www.antenna-theory.com/basics/whyantennasradiate.php and
http://farside.ph.utexas.edu/teaching/em/lectures/node94.html )
This theory, concentrated on the “current in the wireö, was leading to the
development ofthe traditional antennas as: dipols, yagis, LPSs, verticals,
loops and so on. This theory is correct, however it does not represent the
full truth. Only one half of the physics is considered here, because EM waves
are not only generated by time varying magnetic fields, but also by dynamically
varying electricfields. This fact became clear to me by studying the Maxwell
equations, and by thoughts gained through quantum physics, especially through
the behaving and the properties of photons.
See(
http://en.wikipedia.org/wiki/Maxwell's_equationshttp://en.wikipedia.org/wiki/Photon )
In the Maxwell equations you find the Gauss’ law, the Maxwell-Faradays law of
induction, and the expanded Ampère’s circuital law. They describe the dynamic
interaction of the curly electric and magnetic field, and the current.
Technical handbooks treat EM waves throughout as waves, generated by
oscillating current in a conductor, where the radiation begins. Accordingly
the formulas are established. The frequently used antenna simulation program
NEC (EZNEC) and its family does not (yet) allow to define and simulate of my
new antenna construction. As a consequence, special äantenna rules“ were
createt, based on this one-side view. As an example, good antenna texts lists
the following "golden rules" for antenna design:
1. Much wire in the air will bring the best results
2. As high as possible (antenna at ground level is bad)
3. Current radiates (ARRL Handbook: current produces the radiated signal)
Furthermore, most antenna books write, that antennas with the higher radiation
resistance radiate more, and that short antennas generally have a very low
efficiency.
All these above rules are based on the experience gained during many years of
work with traditional wire antennas. Now I don’t want to say, that these rules
are wrong, but I have to limit applicability of them: They are only valid for
antennas based on the physical law of wave generation by oscillating currents
in a conductor.
Traditional antennas are based on this principle. However, when the RF current
flows though an area, then new properties appears. E.g. with short radiators a
much higher radiation resistance is obtained, than the formulas states, that
the formulas based on the dipoles! An area forms a capacity, which produces a
strong E field. By build an antenna, which bases on the open dynamic E field,
then the old formulas does not apply, as here other formulas apply for this
case.
The intention for my new antenna design was, to produce a maximum dynamic E
field in the space around the antenna.
During the last years I built such antennas and conducted many field tests,
comparing this antenna with traditional wire antennas.
The result was, that an antenna with 150cm radiator length (= 5 feet) at a
wavelength of 40m produced constantly the same signal strength, and many times
a stronger signal at the remote station, by comparing with dipols, verticals,
G5RV, FD3, and longwires. The transmit power and the location were identical,
and during the qso many switchovers between the test antenna, and comparing
wire antenna were made.The hight above ground of the base of the new antenna
was only 50cm to 150cm, while the comparing antenna was in its original hight!
Hundreds of tests were made from 10m to 160m wavelength, and always the same
result was obtained. The length of the radiator on 160m was just 3m!I published
many of these tests in the internet under “New HF Antennaö.
The following criterias apply for the “New HF Antennaö:
- areas (planes) are used, which form in the space a capacity, in which the E
field is produced.
- these areas have to be arranged in a special manner, open into space (a
capacitor with two directly opposed plates produces practically no radiation).
- the feedline may not be part of the antenna. The line is not allowed to
radiate.- feeding of the antenna has to be floating, without reference to
ground.
- the impedance has to be adjusted such, that the SWR is below 1.5
- the dimension of the areas has to be small in relation to the wavelength.
(Length of the radiator < 7% of the wavelength, otherwise the phase difference
of the E field is reducing the radiation efficiency).
In my realisation, feeding is made by the “varylinkö. This is part of the
antenna structure and permits to obtain a SWR below 1.1 on each band. This has
the advantage, that the antenna does not require an antenna tuner.
Other realisations:
Others have also developed antenna types, which are using the principle of E
field wavegeneration.
E.g. Isotron, Microvert, EH-Antenna (Crossfield antenna CFA) and similars.
All these realisations do not fulfill all criterias listed above, and therefore
their efficiencyis 8 db to 18 db less than the “New HF Antennaö.
Future:
Development of additional versions of this antenna continues. The significance
of this antenna will be important, due to many restrictions in available space,
and regulations to errect traditional antennas with their large physical
dimensions.
73, Felx, HB9ABX (felix-abx at gmx.ch)
Read previous mail | Read next mail
| |
