Radiation Leakage of Before-Sale and Used Microwave Ovens

Methods

Prior to carrying out microwave leakage measurements, all surveyed models of before-sale and used microwave ovens were inspected for labeling, interlock functioning and the integrity of the door, hinges and seals. Other relevant information such as oven age, manufacturer and maximum output (microwave) power was also recorded.

Measurements of maximum microwave leakage, in terms of power density, emanating from all external surfaces of the ovens were conducted at 5 cm from all external surfaces with the cavity empty and with the cavity containing a 275 ml water load in a low form beaker. All the inspected ovens were adjusted to operate at maximum output power. The measurements were made using an electromagnetic radiation monitor (Narda 8110B) together with the following probes:

1. NARDA 8120A, rated for a maximum power density of 2 mW/cm² and a minimum sensitivity of 0.01 mW/cm²
2. NARDA 8121A, rated for a maximum power density of 20 mW/cm² and a minimum sensitivity of 0.1 mW/ cm².

Figure 1. Graph showing leakage data of before-sale ovens with and without load.