A tunable microwave applicator for extraction of date-juice and similar products

A tunable microwave applicator for extraction of date juice and similar products has been developed, designed and constructed. It consists of two main units: a microwave unit and a press/filter unit. The microwave unit consists of a tunable cylindrical cavity resonator, a section of aluminum waveguide with aperture coupling and tuning mechanism and a locally assembled microwave generator working at 2.45 GHz. The press/filter unit is made from a low-loss, heat-resistant material that works inside the cavity. Performance tests at both low and high power levels showed good performance characteristics with power conversion efficiency of more than 70%. Comparison with a commercial microwave oven and an electric heater showed the superiority of the present applicator, in terms of heating rate and power coupling efficiency.