Why does the home microwave operate at 2450 MHz and the industrial unit at 915 MHz?
Microwave ovens operate at 2450 MHz with low-power (600-1500 Watts), inexpensive, reduced-size magnetrons and waveguides, allowing for a compact package and small load or throughput. Industrial microwave applicators operate at 915 MHz with high power (100 kilowatts), a much larger applicator and consequently much greater throughput. The efficiency of a 2450 MHz magnetron is only about 60%, while the efficiency of a 915 MHz, 100 kW magnetron is 88%. Therefore, the 915 MHz operating costs will be less. In addition, one 100 kW, 915 MHz magnetron is about 50% of the price of seven 15 kW, 2450 MHz magnetrons. Finally, the penetration depth of 915 MHz magnetrons is about 3 times greater than a 2450 MHz magnetron.
