About "new generation antennas". Encyclopedia of radio electronics and electrical engineering

Encyclopedia of radio electronics and electrical engineering / Television antennas

 Comments on the article

From time to time there are reports of inventions of "new antennas with special electrophysical properties". So 40 years ago there was a boom in "water" antennas assembled in an ordinary light bulb filled with distilled water, there were tales about the "special properties of mercury antennas", etc. air or airless space. This circumstance prompted them to "invent" ultra-small-sized but full-sized antennas with all the ensuing benefits. So the epsilon near the water is about 1, respectively, and the antenna can be reduced by the same amount. Today we are talking about modern composite materials with a permittivity much greater than 80 and antennas based on them. Indeed, such working antennas can be created, and are being created by various companies, for example, for satellite reception. But these working antennas are still not subminiature, as in the indicated brochure.

The amount of energy of radio waves incident on a certain surface is directly proportional to the area of ​​this surface and it is impossible to increase it by any "shamanic dances with a tambourine". NO composite materials or gilding can change this law of nature.

So, are these small antennas a bluff or a hoax? Not! They may work and be useful, but not because of the use of "special composite materials". As can be understood from the prospectus under discussion, we are talking not just about antennas, but about a bunch of antenna-amplifier, otherwise "active antennas".

To enable radio reception, the level of the useful signal delivered to the input circuits of the receiver (TV) must at least exceed the level of the latter's own noise, reduced to its input. To improve the signal-to-noise ratio of the radio receiving path, antenna amplifiers installed directly near or on receiving antennas have long been successfully used. An already amplified signal arrives through the drop cable to the receiver (TV), so cable losses or interference induced on it no longer degrade reception so much. In addition, if the intrinsic noise (noise temperature) of the antenna amplifier is less than that of the receiver (TV), then an improvement in reception will be observed even if the antenna amplifier is installed below, directly at the input of the receiver. Such amplifiers, using modern low-noise transistors, exist and are constantly being improved.

So the use of composite materials in the antenna allows you to create small-sized, broadband, optimal receiving antennas, the main disadvantage of which is the low level of the received signal (due to its small area), which is compensated by the built-in antenna amplifier. And such synthetic antenna systems can replace traditional full-sized "air" antennas.

Moreover, their small size adds a new quality to them - spatial positional selectivity. In urban conditions, due to multiple reflections, re-emissions and signal interference, radio wave fields have a very complex spatial structure. Traditional full-size receiving antennas are affected by both the desired signal and its reflections, causing ghosting, fringing, fading, and increased noise on the TV screen. Very often, the spatial arrangement or orientation of the radiation pattern of such antennas cannot completely get rid of these shortcomings, especially with wideband reception. With an antenna of small dimensions, it is certainly easier to find a point in space with minimal interference. But the signal field is constantly changing due to weather conditions, building changes and many other factors. Therefore, such miniature antennas are especially promising as indoor antennas, easily moved by the user for the best reception quality.

As for long-range and ultra-long-range reception, then full-sized directional antennas, with the same low-noise antenna amplifiers, will always surpass small-sized ones in quality, and in the very possibility of receiving a signal.

Unfortunately, in the brochure under discussion, as often happens in advertising, in my opinion, there are errors and inaccuracies:

"The various types and types of receiving and transmitting antennas currently used have various disadvantages, and the main one is large sizes (up to 10 m)."

Antennas are big, aren't they? It is not necessary to attribute to small-sized substitute antennas the ability to radiate a signal as efficiently as conventional antennas. Their destiny is radio reception.

"A new approach to the physical process of receiving and transmitting electromagnetic waves is based on the theory of electromagnetic wave length reduction in the volume of a composite material, the use of a composite material as an active element of an antenna-feeder device with an energy potential"

And what's new here? Dielectric antennas have been known for a very long time, including active ones. Antennas in composite materials were made at the Tiraspol plant "Moldavizolit" about 15 years ago ... I just want to add "... and receiving a useful signal directly from the noosphere!"

"The possibility of a significant increase in the density of radio channels in the operating frequency range"

What, what? Antenna will condense radio channels? Fiction! If we mean the polarization decoupling of groups of channels, then this can be done by any antenna with wave polarization.

"Reducing the energy of the radio channel"

This is some nonsense! Radio engineers use more powerful transmitters and higher gain antennas to INCREASE the energy of the radio channel and improve the signal-to-noise ratio. Here they rejoice in the opposite?!

"The quality of signal reception, with antenna sizes many times smaller than analogues, is not inferior to 'large' traditional antennas"

It is not correct to compare active and conventional antennas. And even then this is possible under certain conditions (urban). A comparison of "pure" antenna devices of the same configuration will never even reveal the alleged equality of these antennas.

"The ability to work on the reflected wave and in the conditions of intermodulation distortion"

Maybe you mean signal interference? Intermodulation distortion is somewhat different ... not from the field of antennas, but is typical for amplifiers, receivers, transmitters.

"There is no information on the release or development of alternative antennas using technologies of this level (at the time of obtaining a patent)"

You can also patent a paper clip by changing its shape or covering it with plastic so that it does not rust and stain documents ...

In the journal "Radio" about 25 years ago, an active automobile antenna of the SV-LW range was described with similar dimensions, providing an equivalent effective height of several meters. For at least 6 years, Lucent Technologies has been using GPS receivers with an active satellite dish in its CDMA cellular stations. It consists of a 5cm multi-threaded coil and a solid state amplifier providing a total gain of 28dB. There are also many portable GPS receivers…. So something is still being done in the world.

And finally, I want to talk about a place where miniature broadband antennas can certainly be very useful - in parabolic or other reflector antennas.

Parabolic antennas are broadband initially, often spoiled by the narrowband of their feeds. Having collected the signal to a point (spot) with a parabola, it is difficult to make a puller for it. traditional antenna elements are too large. Therefore, for example, in MMDS networks, a parabola is made with different surface curvature, in orthogonal planes, adjusting its focusing property to the linear feed used. The use of miniature dielectric antennas as a feed will make it possible to create truly broadband antennas with high gain based on a paraboloid of revolution.

Summing up, I will say that miracles do not happen, and you have to pay for everything either by loss of sensitivity or additional costs for a low-noise and broadband powered amplifier. A crackling advertising is just a marketing ploy.

Author: E.Shustikov, UO5OHX ex RO5OWG; Publication: shustikov.by.ru

See other articles Section Television antennas.

Read and write useful comments on this article.

<< Back

Latest news of science and technology, new electronics:

Artificial leather for touch emulation 15.04.2024

In a modern technology world where distance is becoming increasingly commonplace, maintaining connection and a sense of closeness is important. Recent developments in artificial skin by German scientists from Saarland University represent a new era in virtual interactions. German researchers from Saarland University have developed ultra-thin films that can transmit the sensation of touch over a distance. This cutting-edge technology provides new opportunities for virtual communication, especially for those who find themselves far from their loved ones. The ultra-thin films developed by the researchers, just 50 micrometers thick, can be integrated into textiles and worn like a second skin. These films act as sensors that recognize tactile signals from mom or dad, and as actuators that transmit these movements to the baby. Parents' touch to the fabric activates sensors that react to pressure and deform the ultra-thin film. This ... >>

Petgugu Global cat litter 15.04.2024

Taking care of pets can often be a challenge, especially when it comes to keeping your home clean. A new interesting solution from the Petgugu Global startup has been presented, which will make life easier for cat owners and help them keep their home perfectly clean and tidy. Startup Petgugu Global has unveiled a unique cat toilet that can automatically flush feces, keeping your home clean and fresh. This innovative device is equipped with various smart sensors that monitor your pet's toilet activity and activate to automatically clean after use. The device connects to the sewer system and ensures efficient waste removal without the need for intervention from the owner. Additionally, the toilet has a large flushable storage capacity, making it ideal for multi-cat households. The Petgugu cat litter bowl is designed for use with water-soluble litters and offers a range of additional ... >>

The attractiveness of caring men 14.04.2024

The stereotype that women prefer "bad boys" has long been widespread. However, recent research conducted by British scientists from Monash University offers a new perspective on this issue. They looked at how women responded to men's emotional responsibility and willingness to help others. The study's findings could change our understanding of what makes men attractive to women. A study conducted by scientists from Monash University leads to new findings about men's attractiveness to women. In the experiment, women were shown photographs of men with brief stories about their behavior in various situations, including their reaction to an encounter with a homeless person. Some of the men ignored the homeless man, while others helped him, such as buying him food. A study found that men who showed empathy and kindness were more attractive to women compared to men who showed empathy and kindness. ... >>

Random news from the Archive Electric car Mercedes-Benz VISION EQXX 07.01.2022 By the end of the decade, the German automaker Mercedes-Benz intends to completely abandon the production of new models of passenger cars with internal combustion engines, so the brand is showing its potential in the field of electrification at the first opportunity right now. Another concept impresses with a power reserve of more than 1000 km and record-breaking aerodynamics. The VISION EQXX Concept is the fruit of further efforts by Mercedes-Benz to improve the efficiency of electric vehicles. The efficiency of the power plant, for example, was brought up to 95% - only five percent of the energy stored in the traction battery is lost when torque is transmitted to the wheels. Experts from the Mercedes-Benz racing team took an active part in the creation of the prototype, and the traction battery received an impressive charge storage density of about 400 Wh / l. As a result, it provides a capacity of just under 100 kWh, with half the size and 30% reduced weight compared to existing analogues. At the same time, the battery supports the ability to charge from a network with a voltage of up to 900 volts. The peak power of the power plant reaches 150 kW. The wheelbase of 2800 mm is not that great by the standards of other cars of the brand, which allows the manufacturer to consider this concept a compact electric car, although the pursuit of an outstanding drag coefficient of 0,17 forced engineers to equip the car with a rather long rear overhang. An electric car has less aerodynamic drag than an American football, second only to a penguin in form efficiency. The use of high-strength steel to create a power frame made it possible to reduce the curb weight of the electric vehicle to 1750 kg without compromising passive safety. In the decoration, materials obtained from the recycling of waste are actively used. Mercedes-Benz is particularly proud of the energy consumption for moving an electric car per 100 km - for the VISION EQXX it does not exceed 10 kWh. Such energy consumption is comparable to the efficiency of a gasoline car, which consumes no more than 100 liter of fuel per 1 km. The power reserve of VISION EQXX on a single charge reaches 1000 km. The cooling system of the power plant is equipped with active shutters, which open the access of outside air to the engine compartment and throw out the heated air through slots in the hood. The heat pump, which is involved in heating the passenger compartment and the traction battery, is also designed with an emphasis on energy efficiency. Even the shape of the wheel covers was designed with aerodynamics in mind, and tires with low rolling resistance were provided by the Bridgestone brand. On the roof of the electric vehicle, there are 17 solar panels, which in clear weather can increase the driving range by 25 km per day. In the cabin of the concept, you can find a unique display with a diagonal of 47,5 inches and a resolution of 7680 x 600 pixels, extending from the left to the right A-pillar and made using mini-LED technology.

Other interesting news:

▪ Integration of smoke detectors into computers and mobile devices

▪ 10000 PPI OLED display

▪ Golden water block

▪ Linear Voltage Regulator LT3021

▪ Acer Aspire S7 update

News feed of science and technology, new electronics

Interesting materials of the Free Technical Library:

▪ section of the site Data transfer. Article selection

▪ article Cut under a nut. Popular expression

▪ Article What color is Mars? Detailed answer

▪ article Work on high-frequency installations for the manufacture of binding covers. Standard instruction on labor protection

▪ article Refinement of programmers for guaranteed programming of PCF8582 microcircuits. Encyclopedia of radio electronics and electrical engineering

▪ article Moving picture. Focus Secret

Leave your comment on this article:

All languages ​​of this page

Arabic	Hebrew	Polish
Bengali	Hindi	Portuguese
Chinese	Italian	Spanish
English	Japanese	Turkish
French	Korean	Ukrainian
German	Malay	Vietnamese

Home page | Library | Articles | Website map | Site Reviews

www.diagram.com.ua
2000-2024