16th International Conference
on Microwave and High Frequency Heating

18-21 September 2017, Delft, The Netherlands
14:30   Microwave and high frequency supply design
Chair: Junwu TAO
14:30
15 mins
LOW-NOISE, HIGH-EFFICIENCY AND HIGH-QUALITY MAGNETRON FOR MICROWAVE OVEN
Nagisa Kuwahara, Takeshi Ishii, Keita Hirayama, Tomohiko Mitani, Naoki Shinohara
Abstract: We developed a low-noise, high-efficient and high-quality magnetron for microwave ovens, which is called U-version. The development purposes of this magnetron are an agreement to CISPR11 and an achievement of excellent energy saving performance. In fact, it is technically very difficult to make a low noise with high degree of efficiency. In order to solve this problem, we use the CAE technology and the theory. In addition, we achieved a high quality product, utilizing the technology of Panasonic Industrial Magnetrons. As the figure 1 shows, this product has still realized a longer life time, which is more than 3,500 hours.
14:45
15 mins
ACTIVE-ANTENNA SCHEMES FOR SOLID-STATE MICROWAVE HEATERS
Eli Jerby, Amir Shelef, Shahar Shalom
Abstract: The current technological efforts to implement solid-state amplifiers (SSA’s) in microwave-heating applicators are naturally focused at the SSA advantages over magnetrons, such as their superior controllability, frequency variability, etc. [1]. However, in some cases this perfection may lead to over-sophisticated solutions and to costly design expenses, which may impede the SSA-technology penetration into basic low-cost markets. Here we study various simplified schemes, based on the active-antenna concept, which integrate the SSA and the antenna together. This combined radiating-oscillator device, directly fed by a DC voltage, is expected to be cheap and user friendly in mass production. A miniature solid-state microwave heater based on this approach was already presented in 2006 [1] (a solid-state microwave-drill version of it was introduced soon after [2, 3]). Here we study similar active microwave-heating applicators in various schemes, using the LDMOS transistor in a positive feedback-loop which includes the radiator. These low-cost integrated units could be more easily incorporated in microwave-heating devices, with a minimal design effort. Various schemes, such as a solid-state magnetron-retrofit and an integrated LDMOS-antenna, are introduced. References 1. AMPERE Newsletter, Special Issue on Solid-State Microwave Heating, Jan. 16, 2017 (www.ampere-newsletter.org) 2. Schwartz, E., A. Anaton, D. Huppert, E. Jerby, Proc. IMPI 40th Int'l Microwave Symposium, pp. 246-249, Boston, Aug. 9-11, 2006. 3. Mela, O., E. Jerby, Proc. Global Congress on Microwave Energy Applications (GCMEA-1), pp. 443-446, Otsu, Japan, August 4-8, 2008. 4. Meir, Y., E. Jerby, IEEE Trans. Microwave Theory Tech., 2012, 60, 2665-2672.
15:00
15 mins
EMERGING MICROWAVE APPLICATIONS IN FOOD, CHEMISTRY, ARTIFICAL DIAMONDS, POLYMERS AND WASTE
Daniel Baars, Klaus Martin Baumgaertner, Markus Dingeldein, Markus Reichmann, Niko Voit
Abstract: 16th International Conference on Microwave and High Frequency Heating AMPERE 2017, Delft, The Netherlands, September 18-21, 2017 EMERGING MICROWAVE APPLICATIONS IN FOOD, CHEMISTRY, ARTIFICAL DIAMONDS, POLYMERS AND WASTE Daniel Baars, Klaus Baumgärtner, Markus Dingeldein, Markus Reichmann, Niko Voit Muegge GmbH, Hochstrasse 4-6, 64385 Reichelsheim, Germany info@muegge.de Keywords: food, artificial diamonds, heating, drying, pyrolysis, recycling, renewable energies, compact head, solid state Industrial heating by microwaves is required for processing of an emerging number of novel materials in a large variety of application areas, e.g. (re)heating, baking, tempering, dehydration, pasteurization, sterilization, and puffing in food industry, drying and sterilization in pharmaceutical industry, pyrolysis and recycling in chemical and waste industry, and drying and hardening in polymer industry. Microwave technology is also the basis for integration in emerging plasma technology applications such as diamond growth which requires microwave generator technology to supply a preeminent consistency concerning the stability of power and frequency during operation over a long period of time. Different demands and specifications call for individual and customized solutions concerning coupling of the microwave to the material, necessary microwave power level, and microwave frequency to be applied. Small dimensions for size optimization, avoidance of down-time as well as cost effectiveness are more and more relevant. Establishing small-size and inexpensive solutions, fundamentally minimizing service costs by omitting the magnetron tubes working with limited service life, solid-state components will lead to an enormous growth of solid-state technology in microwave power supplies. In view of facilitating high-power microwave applications, new concepts towards multi-channel processing based on solid-state power supplies will need to be developed.
15:15
15 mins
ONLINE MEASUREMENT OF MAGNETRON RIEKE REFLECTION COEFFICIENT
Vladimir Bilik
Abstract: We have developed a method enabling to observe a magnetron’s Rieke diagram-related load reflection coefficient Gamma_R online, i.e. during a real, full-power operation of any installation into which a high-power vector reflectometer (HPVR) can be integrated. To achieve this, the HPVR-measured reflection coefficient Gamma_A must be transformed by certain fictitious equivalent linear two-port circuit. For obtaining scattering parameters of this circuit, two vector network analyzer calibrations must performed, one with the magnetron antenna probe installed in the magnetron reference launcher as stipulated in the magnetron datasheets (Fig. 1a), the other with the probe installed in the actual customized user launcher (Fig. 1b). The two obtained S-parameter matrices (SR, SA) can then be combined to arrive at the desired S-parameters of the transforming two-port. To verify the approach, we have carried out experiments using a 2M244 magnetron, a customized WR340 waveguide launcher, and a WR340 waveguide-based autotuner serving as HPVR. The comparison of the obtained measurement results with the direct Rieke reflection coefficient measurement using the reference launcher as well as the comparison with the published Rieke diagram have validated, within the estimated experimental error, the correctness and usability of the devised method.