A Smart Fluorescent Antenna for Wi-Fi Applications
Fluorescent Antenna
Fluorescents are a big family of light sources. There are three major types of fluorescent lamps: cold cathode, hot cathode, and electroluminescent. They all use phosphors excited by electrons to generate light. In this article, we will talk about the cold and hot cathode; the electroluminescent lamps are used as “fluorescence” but are so different that they will be covered in another page. From this point onwards, whenever a reference is made to ‘fluorescent lamp’ then it is understood that it is a lamp with a glass discharge tube and fluorescent coating on the inside – this is how the cold and the hot cathode type of lamps are designed. Induction lamps are a type of fluorescent lamps, but they don’t have electrodes.
The standard fluorescent lamp was developed for commercial use during the 1980’s. The idea of the fluorescent lamp had been around since the 1880’s, however, it took the steady work over the decades to finally create a working commercially viable model. This work was done by many, but not bye one single inventor. See our inventors list to learn more.
What are Fluorescent Light Tubes?
A fluorescent light tubes are a low-pressure mercury-vapor gas-discharge lamp that uses fluorescence to produce visible light. An electric current in the gas excites mercury vapor, which produces short-wave ultraviolet light that causes a phosphor coating on the inside of the lamp to glow. A fluorescent lamp converts electrical energy into useful light much more efficiently than incandescent lamps. The typical luminous efficacy of fluorescent lighting systems is 50–100 Lumens per watt, several times the efficacy of incandescent bulbs with comparable light output, but less than that of a typical LED bulb.
Fluorescent Light Tube Circuit
Fluorescent lamp fixtures are more costlier than incandescent lamps because they require a ballast to regulate the current through the lamp, but the lower energy cost typically offsets the higher initial cost. Compact fluorescent lamps are now available in the same popular sizes as incandescent ones and are used as an energy saving alternative in homes.
Fluorescent Light Tube Circuit
Because they contain mercury, many fluorescent lamps are classified as hazardous waste. The United States Environmental Protection Agency recommends that fluorescent lamps be segregated from general waste for recycling or safe disposal, and some jurisdictions require recycling of them.
How Fluorescent Light Tubes Works?
When the switch is on, full voltage comes across the tube light through the ballast and the fluorescent lamp starter. No discharge happens initially, i.e. there is no lumen output from the lamp such that full voltage first glow discharge is established in the starter. This is because the electrode gap in the neon bulb of starter is much lesser than that inside the fluorescent lamp. Then,the gas inside the starter gets ionized – due to this, full voltage builds and heats the bimetallic strip, which is caused to be bent to connect to the fixed contact. Current starts flowing through the starter.
Although the ionization potential of the neon is a little bit more than that of the argon, yet due to small electrode gap, high voltage gradient appears in the neon bulb and hence glow discharge begins in the starter. As the voltage gets reduced due to the current, it causes a voltage drop across the inductor – the strip cools and breaks away from the fixed contact. At that moment, a large L di/dt voltage surge comes across the inductor at the time of breaking.
This high-valued surge comes across the tube light electrodes and strikes penning mixture (mixture argon gas and mercury vapor). The gas discharge process continues and the current gets path to flow through the tube light gas owing to low resistance as compared to the resistance of the starter. The discharge of mercury atoms produces ultraviolet radiation, which in turn excites the phosphor powder coating to radiate visible light. Starter gets inactive during the operation of tube light.
Fluorescent Antenna for Wi-Fi?
This invention employs an ionized gas enclosed in a tube as the conducting element of an antenna. When the gas is electrically charged or ionized to plasma, it becomes conductive and allows radio frequency signals to be transmitted or received. When the gas is not ionized, the antenna element ceases to exit. The invention features a smart fluorescent antenna with a 3G/3.75G/4G router for Wi-Fi applications. The antenna operates at the 2.4 GHz frequency band, which is suitable for Wi-Fi applications. A commercially available fluorescent tube, measuring 0.61 meters in length by 0.25 meters in diameter, is used as the plasma antenna. The gas inside the tube is a mixture of argon and mercury vapor, in the ratio 9:1.
The tube is energized by a 240 V current, provided by a standard AC power supply. A glowing tube indicates that the gas inside the tube has been ionized to plasma and forms a plasma column. In this state, the plasma column becomes highly conductive and can be used as an antenna. A coupling sleeve is positioned at the lower end of the tube, which is used to connect the plasma tube to the router. The function of the coupling sleeves is to store the electrical charge. When the gas inside the tube is sufficiently ionized into a plasma state, it becomes conductive and allows radio
Frequency signals to be transmitted or received. Measurements indicate that the plasma antenna yields a return loss over 10 dB in the 2.23 GHz to 2.58 GHz frequency bands. The antenna’s ability to operate as either a transmitter or receiver in this particular frequency band has been verified through a series of wireless transmission experiments. The performance of this antenna was measured using the Wi-Fi Received Signal Strength Indicator (RSSI) technique. The product was tested for a month in the University Technology MARA’s High Frequency Antenna Laboratory. Our results show that the signal is stronger and more stable compared to others signals.
Wi-Fi Routers in Fluorescent Blubs
Wi-Fi routers are essentially two-way radios that connect digital devices to the Internet. But in many buildings, providing complete coverage is a challenge. Radio “dead spots” can occur in areas where solid walls or appliances block a router’s signal entirely, or degrade it to become so weak that a portable Wi-Fi device, such as a tablet or phone, cannot connect reliably.
Wi-Fi Routers in Fluorescent Blubs
When electricity flows through the argon-mercury vapor in a fluorescent tube, it forms an ionized gas or plasma. Plasma has conducting properties comparable to a common metal radio antenna. This allows an attached router to send and receive radio signals through the light tube on the standard 2.4-gigahertz Wi-Fi frequency in exactly the same way as it does through a regular antenna. The router’s radio waves can ionize the gas in the tube, so it acts as an antenna whether the light is on or off.
According to the research team, the plasma found in a standard 62-centimeter light tube is highly conductive and signal measurements on a test device\ show that it’s strong and stable. Thus, plasma compares favorably with standard metal Wi-Fi antennas for transmitting and receiving. The prototype antenna consists of a fluorescent tube that connects to the router through a tuned wire coil in a sleeve slipped over one end. The coil passes the router’s radio signal through the glass of the fluorescent tube and into the plasma.
The team says that multiple antennas could be connected to a single router through a building’s electrical wiring using existing Wi-Fi standards. This would create a separate antenna in every room where there is a dedicated fluorescent light fixture and provide low- cost building-wide wireless Internet coverage.
Fluorescent Light Common Uses
Fluorescent light is common in lamps: both outdoor and indoor;fluorescent light is used as back light for LCD displays; decorative lighting and sings, and both in high bay and small area general lighting. Not used for lighting from afar due to the diffuse nature of the light.
Fluorescent Light Tube Advantages
- Energy efficient- so far the best light for interior lighting
- Low production cost (of tubes, not of the ballasts)
- Long life of tubes
- Good selection of desired color temperature (cool whites to warm whites)
- Diffused light (good for general, even lighting, reducing harsh shadows)
Disadvantages of Fluorescent Light Tube
- The flicker of the high frequency can be imitated to humans (eye strain, headaches and migraines)
- Flicker of common fluorescent light looks poor on video, and creates an ugly greenish or yellow hue on camera.
- Diffused light (not good when you need a focused beam such as in a headlight or flashlight)
- Poorly/cheaply designed ballasts can create radio interference that disturbs other electronics
- Poorly/cheaply designed ballasts can create fires when they overheat
- There is a small amount of mercury in the tubes
- A Imitating licker at the end of the life cycle.
A Fluorescent lighting system consists of two or three main components: (1) The fluorescent lamp, (2) The Ballast, and (3) the Starter system. Depending on the particular fluorescent lighting system, the starter may be a replaceable component, a starter may not be required, or the starter function may be integrated into the ballast. The starting function may also rely on the physical design of the fixture.
The basic concept behind a fluorescent lamp is that a flow of electrical current occurs between two metal conductors placed in a glass tube, a process also known as arcing. That current flow passes through the gases in the tube (argon and a small amount of mercury in a gaseous phase) and excites the atoms of gas. The excited atoms emit photons, some of which are vibrating at a frequency known as ultraviolet light. The ultraviolet light strikes a phosphor coating on the inside of the glass. The phosphor responds to the ultraviolet light by producing a bright visible light.
This all sounds simple enough, but by itself, a fluorescent lamp won’t do anything. For a fluorescent lamp to start working, the potential of the electricity provided to the electrical conductors (called cathodes) inside the lamp must be greater than the initial electrical resistance of the gas in the lamp so that the electricity may begin arcing through the gas.
There are two ways to overcome this initial electrical resistance: (1) Lower the electrical resistance of the gas in the lamp, or (2) temporarily raise the electrical potential supplied to the lamp to a level greater than the resistance of the gas, so that arcing may begin. The Starter (or if absent, the Ballast) creates either or both of these conditions to start the lamp. In fact, up to half of the wiring in some fluorescent fixtures is used only while starting the lamps. There are three different systems used in starting a traditional fluorescent lamp: preheat, rapid start and instant start.
Thus, this is all about fluorescent light tubes and their types. We hope that you have got a better understanding of this concept. Furthermore, for any queries regarding this concept or to implement any electrical and electronic projects, please give your valuable suggestions by commenting in the comment section below. Here is a question for you, what are the applications of fluorescent light tubes.
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