DIMAS at the EuMW Conference 2018

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The Microwave Division of ITACA will participate as exhibitor in European Microwave Week 2018 Conference that will be held in Madrid, Spain from the 23rd to the 28th of September.

Bringing industry and academia together, EuMW 2018 is a SIX day event, including three cutting edge conferences and one technology exhibition. EuMW 2018 provides access to the very latest products, research and initiatives in the microwave sector. It also offers the opportunity for face to face interaction with those driving the future of microwave technology.

In our booth (No. 14), people will be able to see:

  • Innovative microwave equipment for processing and synthesis of high-tech materials with unique properties.
  • Advanced technology for testing and characterization of electromagnetic properties of materials from room to high temperatures (>1000ºC).
  • Equipment for in situ combination of different techniques (i.e. simultaneous dielectric and Raman spectroscopy) during microwave processing, allowing a fine-tuning control and a deeper understanding of microwave-matter interaction.
  • Our expertise in electromagnetic modeling and design of microwave equipment for emerging challenges and novel applications.

Some recent results about electromagnetic characterization obtained with our technology will be presented in the conference as well:

  • David Marques-Villarroya et al., “Extended Full-Wave Analysis of a Multimode Circular Cavity with Insertion Hole”

Dielectric Kit for Materials Characterization at Microwave Frequencies

Dielectric materials have many applications ranging from microwave components and subsystems to industrial and manufacturing processes. Often in these applications, a successful design greatly depends on an accurate knowledge of the complex permittivity of the materials at these frequencies.

The Dielectric Kit for Vials is a new instrument developed by the Microwave Division of the institute ITACA to determine the complex permittivity (dielectric constant and loss factor) of a wide range of liquid, granular or powdered materials around the ISM frequency of 2.45 GHz. It is a complete solution which includes all necessary components to perform the generation, control and analysis of microwave signals, calculation of dielectric properties and display of results.

Two versions of the Dielectric Kit for Vials have been designed depending on the sample volume (with standard vials of 1mL or 8 mL). The measurement probe dimensions have been optimized in each case to provide repeatability and high accuracy in the determination of materials dielectric properties. Unlike other available equipment, calibration and adjustment with reference liquids is not necessary, and measurement of sample dielectric properties is fast and convenient.

OPERATION PRINCIPLE

The equipment comprises a source (PLL Microwave Synthesizer), which generates the microwave stimulus, a set of directional couplers to separate reflected and transmitted signals, a microwave receiver based on the AD-8302 integrated circuit for magnitude and phase detection and a measurement probe, where the material to be measured is placed. A control unit (Microprocessor System) is connected through a USB link to a personal computer which includes all the required processing to determine dielectric properties from the measurements and to transform the outputs into the desired representation.

The dielectric probe is designed as a microwave resonator where the interaction of the signals with the material takes place. Vials containing the material under test are introduced in the microwave resonator though a hole at the top of the probe. After sample insertion, the probe response (resonant frequency and quality factor) is shifted depending on the sample dielectric properties. From the measurement of the new response, the complex permittivity of the sample is calculated by using the electromagnetic model of the structure by a numerical procedure.

The Vials Dielectric Kit is fully controlled by a Labview-based software, which has been developed to perform all the necessary functions with a user-friendly interface.

EXAMPLES OF MEASUREMENTS

This equipment is specially designed for liquid, granular or powdered materials. Solid materials might be measured if machined in rod shape with the inner vial dimensions. The following table shows some measurements of common materials. Comparisons with other measurement methods or published data are also included.

TECHNICAL SPECIFICATIONS

  • Frequency range: 1.5GHz to 2.6GHz (nominal, limited by MUT properties)
  • Dielectric constant: ε′<100
  • Loss factor: 0.001<ε′′<15
  • Accuracy: About 1% in dielectric constant and 2-5 % in the loss factor
  • Repeatability and Linearity 0.2%
  • Material under test assumptions:  (Minimum sample volume required :1mL (vial external diameter 4.1 mm) or 8 mL (vial external diameter 5.1mm), non-magnetic, isotropic, homogeneous (uniform composition). For granular materials (particle diameter < 2 mm) measurement repeatability is dependent on density variation.
  • Calibration: No calibration is needed
  • Microwave output: 0 dBm
  • Communication with PC: USB
  • Probe Materials: Aluminum
  • Dimensions: 190mm x 230mm x 85mm
  • Operating Temperature: 22-50 °C
  • Required OS: Windows XP/Vista/7

Dielectric Properties at Temperatures up to 350ºC with Dielectric Kit for Vials

The use of microwaves in fields as communications, radar, medicine, biology, agriculture and industrial processes demands accurate knowledge of the dielectric properties of materials and its variations with respect to many factors.

In particular, monitoring variations of materials dielectric properties with temperature is crucial for many applications, in which it is important to predict the materials performance over the whole working temperature range.

In order to provide a suitable technique, the Dielectric Kit for Vials has been equipped with viales_con_temperatura_v01the necessary components for the dielectric characterization of materials up to 350ºC. It allows for continuous verification of the sample complex permittivity and temperature conditions, maintaining its advantages with respect to other methods: accuracy, convenience, and easiness of use.

To illustrate this application, several tests have been performed with different materials placed in 1mL vials, and heated from room temperature to 350ºC. The figures illustrate the variation of the dielectric properties of cross-linked polystyrene (left) and silicon carbide (right) with the temperature. As figures show, this variation can be followed by simple inspection of the dielectric properties given by the Dielectric Kit during the cooling process of the samples.

Diel_properties_with_temperature_v01

DIMAS at ECerS Conference 2015

Ecers2015

The Microwave Division of ITACA will participate as an exhibitor in ECerS 2015 Conference that will be held in Toledo, Spain from the 21st to the 25th of June.

Organized every two years, the ECerS Conference is the place to be for scientists, students and industrialists willing to have a direct access to one of the largest community of international experts of ceramic science and technology.

In our booth, people will be able to see:

  • Innovative microwave equipment for processing and synthesis of high-tech ceramics with advanced and unique properties.
  • Advanced technology for testing and characterization of electromagnetic properties of materials from room to high temperatures (>1000ºC).
  • Equipment for real-time combination of different testing techniques (i.e. simultaneous dielectric and Raman spectroscopy) during microwave processing, allowing a fine-tuning control and a deeper understanding of microwave-matter interaction.
  • Our expertise in electromagnetic modeling and design of microwave equipment for emerging challenges and novel applications.

Some recent results about ceramics processing and characterization obtained with our technology will be presented in the conference as well:

  • Julian Jiménez Reinosa, Beatriz García-Baños, Jose M. Catalá-Civera, Jose Francisco Fernández Lozano, “Microwave sintering processes for ceramic: microwave kinetic effect”, 14th International Conference of European Ceramic Society, June 2015, Toledo (Spain).
  • Rut Benavente, María D. Salvador, Ana Martínez-Amesti, Felipe Peñaranda-Foix, Adolfo Fernández, Amparo Borrell, “Effect of microcracking evolution on the thermal stability of β-eucryptite materials obtained by conventional and microwave methods”, 14th International Conference of European Ceramic Society, June 2015, Toledo (Spain).
  • Álvaro Presenda, María Dolores Salvador, Pedro J. Plaza-Gonzalez, Eliria Pallone, Julieta Ferreira, Amparo Borrell, “Effect of Microwave Sintering on Hydrothermal Degradation of Zirconia-Toughened-Alumina (ZTA) Composites”, 14th International Conference of European Ceramic Society, June 2015, Toledo (Spain).