How do Wi-Fi as well as microwave ovens operate in the same frequency band?

Yes microwave ovens do in fact operate at 2.4 ghz, the same frequency as wifi and Bluetooth . But most wifi radios these days also operate at 5GHz which is not used by microwave ovens…..yet.

A well designed microwave oven captures most of the EM energy inside the box to provide efficient heating and is not a good radiator. So the interference with wifi is minimal and only limited to the time when the oven is in operation and in close proximity to wifi signal.

If we look at the term microwave more generally though, it is that frequency which covers the electromagnetic spectrum between 300 MHz to 300 ghz.

In theory this is a very wide spectrum but in practice you're limited to only those frequencies for which you have decently priced generators available. 2.4 ghz,5 ghz,12 ghz , 24 ghz,60ghz etc etc.

Fun fact cosmic microwave background radiation containing the information about early universe also(as the name suggests) falls within the microwave band.

Comments

Low energy fabrication of a high strength layered ceramic composite for high temperature oxidative environments

High temperature materials are required in various applications: in metallurgy, for making combustion chambers of internal combustion engines ,for the body of Stirling engines, for wall material of nuclear fusion reactors, for the body of Jet engines among a few. For such applications we need materials that can retain their strengths at elevated temperatures and can survive in an oxidative environment It is the second requirement which is more stringent. Although numerous metallic alloys have been synthesized that can sustain both high temperatures and oxygen attack they require complex processing steps On the other hand ceramics are good at resisting both oxygen attacks and high temperatures and are relatively simpler to fabricate but are limited by massive amounts of energy required. For example c/sic composites will perform well in demanding high temperature oxidative environments but require vacuum to be manufactured. The acheson process for the formation of sic is...

Unlocking the Potential of Carbon for Long-Distance Electrical Transmission

ABSTRACT: We present a technique to manufacture large scale carbon based conductors for transmission of electrical energy over continental scale distances. We start by identifying precursors that could be used for production processes.We review the current manufacturing techniques of producing carbon based fibers and explain why certain precursors have dominated carbon materials industry. We identify methods that can be used to increase the yield through alternative precursors.We put forward a theory of why carbon conductors have less conductivity than metals and what can be done to improve it. Finally we postulate that with cheaper production methods even if carbon based conductors are 10 times less effective than poor metallic conductors like steel, they can still outperform them in High Voltage transmission lines if cheap manufacturing techniques could be developed. INTRODUCTION: Copper and in certain very specific applications aluminium & silicon steels dominate when it co...

Do electrons really flow as a beam in cathode ray tubes?

Abstract: It is generally well accepted that a beam of electrons flow from cathode to anode in a cathode ray tube. Taking pressure data from a variety of sources from CRT manufacturers’ data sheets to engineering documents of large hadron colliders we show through calculations that there is enough residual gas in these devices to form a conducting path from anode to cathode due to plasma formation. When high voltages are applied at the anode the gas is ionized and becomes a plasma forming a ‘wire’ between the two electrodes that causes conduction of energy. The objective of this brief note is to encourage scientists and engineers to re-investigate commonly accepted beliefs about vacuum tubes and develop new knowledge that can revitalize the field especially at a time when nano scaled vacuum channel transistors are being envisioned. Most vacuum tubes have operating pressures in the ultra high vacuum range. This is true for cathode ray tubes, vacuum tu...

Force calculations on electron in vacuum tubes

ABSTRACT A claim was made in the paper titled “Do electrons really flow as a beam in cathode ray tubes? ” where we asserted that electrons remain near the cathode surface during the operation of CRT. Here we do force calculations on electrons by estimating the debye length of electrons emitted after thermionic emission and show that under given applied voltages if electrons are placed at debye length they are sufficiently far away from the cathode surface to be accelerated towards it. Debye length, while typically used to measure charge screening distance in plasmas and electrolytes, can also be used to estimate the distance of emitted electrons from the cathode surface. In the same way debye length is used to calculate the thickness of an electrical double layer in which the surface charge and charge on inner helmholtz plane are immobile & the charges on outer helmholtz plane are mobile we can model emitted electrons as mobile charges & image charges distributed on the cathode...

Manufacturing technique for layered carbon /ceramic composite for use in high temperature oxidative environment

We previously described a layered carbon glass material system that is different from c/sic , c/sio2 matrix composites in that it consists of a distinct C/C phase which is coated by an sio2 layer. https://akshatjiwannotes.blogspot.com/2024/12/low-energy-fabrication-of-high-strength.html This material system presents a distinct advantage in a high temperature oxidative atmosphere as the C/C matrix is protected by the oxidation resistant glass shield. Such a material can supposedly be synthesized in an open oxidative atmosphere. In this short note we will answer some questions such as What manufacturing technique will be used? How can silica particles be sintered on the substrate? How can adhesion between sintered particles and carbon substrate be ensured? What, if any ,sintering aids will be used? What would be the mechanical properties of the composite so formed? What level of heat treatment will be required? To make the composite only the minimum amount of heat ...

Electrostatic Machines in Power Engineering: Rethinking Their Role and Future Potential

ABSTRACT: Although electrostatic motors and generators have been among the first electrical machines developed they have not gained widespread adoption in power engineering.Except for very niche applications in micromotors the electrostatic machines have not done well.The electrostatic theory is overlooked & it's the electromagnetic counterparts that are intensely studied in educational institutes. In this paper we explore the reasons behind this fact & propose the design of an electrostatic generator that can compete with its magnetic analogue. INTRODUCTION: Forces due to electrostatic fields are extremely powerful. If a charge is moving at the speed of 1m/sec then the magnetic force due it is 3x10^8 times weaker than the electrostatic force. This should have encouraged engineers & scientists to develop electrostatic motors & generators but it hides a very important point about electrostatic fields. At the magnetic saturation limit the electric field ...

Engineering Design of a Stirling Engine Integrating High-Temperature Combustion and Low-Temperature Cryogenic Sources

Engineering Design of a Stirling Engine Integrating High-Temperature Combustion and Low-Temperature Cryogenic Sources ABSTRACT While Stirling engine analysis using the ideal adiabatic model improves upon the isothermal model by accounting for heat exchange between hot and cold spaces it comes at the cost of complexity requiring the designer to solve for 16 variables and 22 differential equations. Higher order analysis increases the complexity further by using CFD to analyse the engine. None of these methods answer the basic questions about engine design. In this technical report we develop a set of equations that can help design a Stirling engine from scratch by reverse engineering from the power input and calculating plate area,stroke length,piston velocity and frequency of the engine along with the temperature at the hot end. We use the results to calculate the working volume of the engine and the pressure and temperature at the hot side to drive the output. INTRODUC...

Doping strategy for all carbon materials

The challange 1. Carbon is a very small atom. With an atomic number of 6, there are only 5 other atoms that are smaller than carbon. Compared to silicon with an atomic number of 14 the doping choices are minimal. Unlike silicon, elemental carbon can't be melt processed so existing tools & understanding about dopants (or more generally alloying) are out. 2. Carbon has a very rich chemistry. Elements like hydrogen & nitrogen that would become good candidates for doping actually form covalent bonds with carbon[1]. And instead of providing electron-hole pairs, the band gap continuously. Compare this with boron & phosphorus in silicon where they act more or less in their free atomic state. Sure with careful engineering maybe hydrogen & nitrogen can be made to fit inside carbon lattice (nitrogen happily sits inside diamond for example & it would be expected that it would act as a dopant in diamond like carbon as well) 3. The crystal arrangements of carbon that ...

ITU APT foundation of India workshop April 2025

#wififorall At the ITU -APT foundation of India workshop I shared my views with the industry leaders on the benefits of using wifi for offloading traffic from the G networks giving consumers a simpler ,faster,cheaper and more efficient way of connecting to the internet. While I agreed with the participants that it is important to unlock more frequency bands as the demand for data continues to rise, I emphasized that it is also essential for network engineers to recycle & reuse the frequency bands to increase the data transfer rates within the same frequency range. Cellular networks typically create sectors that cover large areas using high power signals increasing the chances of interference. Wifi on the other hand uses low powered devices that rely on small cells to create dense connectivity zones all working in same frequency range. And it works. Nearly every home,every office,every shop has wifi. People are happily using it without reporting any dis...

Nanotechnology or manufacturing ? Which one would I suggest and why?

You know one of the biggest problems in nanotechnology is actually manufacturing of nanomaterials.It turns out that breaking materials (chemically, mechanically or electrically) is not so easy. Neither is doing the opposite i.e bottom up synthesis.Making structural nanomaterials is prohibitively expensive. That is why no one is doing it. I think integrated circuits are probably the biggest success story of nanotechnology. Everywhere else it is still very much a research topic. From the POV of getting a job manufacturing looks more appealing to me. I'm not familiar with the course topics but even in manufacturing you may need to specialise in some material system. Glass,steel,polymers , automation etc. I think instead of choosing between academia or industry, balance it out. Understand the fundamentals of nanotech well enough that you can switch between promising career paths. For nanotech that is semiconductors ,quantum dots,electrospun fibers and maybe membranes. But rese...

Notes by Akshat Jiwan Sharma

Search This Blog