History of Microwaves

History of Microwaves

• The operating principle of radar, invented by the English before World War II, is based on microwaves.
• Dr. Percy Spencer, a researcher for Raytheon Corporation, discovered the effect of microwaves on food in 1945 when a chocolate bar in his pocket melted near a high-power radar.
• The first patent for using microwave energy in the food sector was granted to Dr. Spencer in 1945, and the second patent for microwave roasting of popcorn was granted in 1947.

Development of Microwave Ovens

• The first microwave oven was launched in 1955 for approximately $5,000 (equivalent to $45,000 today) and was large and heavy.
• Initial opinions about the microwave oven were negative due to its size, cost, and fear of radiation emissions.
• By 1964, the price of microwave ovens decreased to around $1,500-$2,000, allowing for the development of portable microwave ovens.
• The first magnetrons produced in Japan were launched in 1968 at a lower price of $500-$1,000.

Applications of Microwaves

• Microwaves have wavelengths ranging from centimeters to millionths of a meter.
• Microwaves are used in satellite communication, local mobile telephone networks, radars, anti-collision systems, and instruments used to study the structure of matter.
• Microwave heaters are used in industrial applications such as drying, roasting, and heating of various products.

Current Status and Future Developments

• Microwave ovens are present in 50% to 75% of kitchens in industrialized countries in Europe.
• The U.S. Airforce is experimenting with the use of microwaves in a new type of electromagnetic bomb, capable of disabling enemy radars, computers, and electronic components.
• Experiments are being conducted to equip missiles and driverless airplanes with electromagnetic bombs that use High Powered Microwave (HPM) rays.

Principle of Operation

• Microwaves are generated by an electromagnetic circuit called a magnetron, which transforms electrical energy at low frequency into an electromagnetic field.
• The electromagnetic field is directed by wave guides into a cavity and reflected by the walls onto the item to be heated.
• The heating process is mainly caused by vibrations of the water molecules in the food item.

Learn about the discovery of microwaves by Dr. Percy Spencer, its relation to radar technology, and the first patents for microwave cooking. Discover how microwaves changed the way we cook and prepare food.