Invited Speakers


The Discussion on the Physics of the Barkhausen Criteria Based on the Second Order Differential Equation

Assoc. Prof. Dr. Pramote Wadkien

Research Field
Telecommunication Network

Affiliation
Department of Telecommunication Engineering, Faculty of Engineering, King’s Mongkud Institute of Technology Ladkrabang, Bangkok,  Thailand 10520

Abstract

From the past to present, the Barkhausen criteria has played an important role for the electrical oscillator design. However, the physical meaning of the loop-gain value in the Barkhausen criteria for practical electrical oscillators is still unclear. In this paper, the Barkhausen criteria based on the second order differential equation has been described. The physical meaning of the loop gain value less than 1, equal 1, greater than 1 a little bit, and greater than 1, are interpreted. Furthermore, the interpretation is confirmed by the result of the practical Weinbridge oscillator’s experiment
Keywords    Barkhausen criteria, electrical oscillators, second order differential equation


Title Hybrid Metamaterial Structure for Asymmetric Horn of Secondary Radar System

Assoc. Prof. Dr. Rangsan Wongsan

Research Field
Antenna and Microwave
Affiliation
Department of Telecommunications  Engineering,  Suranaree  University of Technology, Nakhon Ratchasima, Thailand 30000

Abstract

The hybrid metamaterial is proposed for the performance improvement of an asymmetric horn for the secondary radar system. The hybrid metamaterial is the unification techniques of the structures of wire medium and woodpile Electromagnetic Band Gap (EBG), which designed at the operating frequencies of 1,060 MHz and 1,300 MHz, respectively. We used the EBG structure for improving the radar main beam with horizontal polarization, while the dielectric rods are organized at the right side of the EBG structure to control the direction of main beam at . Besides that, the wire medium structure has been used to improve the main beam of IFF (Identification Friend or Foe) system with vertical polarization and steer its beam shifted to the direction of   comparing with the main beam of radar. In practice, the hybrid metamaterial will be installed in front of the aperture of asymmetric horn with the suitable distance. All appropriated parameters of the proposed hybrid metamaterial are optimized by using CST software. It is found that such the structure can improve the gain of both main beams more than 3 dB when compared to the gain that obtained from the conventional asymmetric horn. Moreover, we could retain the different directions of both main beam as followed in the specification of the original secondary radar system.

Keywords    Horn antenna, Metamaterials, Electromagnetic band gap, Wire medium


One- and two-dimensional modes in the complex Ginzburg-Landau equation with a trapping potential

Assoc. Prof. Dr. Thawatchai Mayteevarunyoo

Research Field
Optic / Physic
Affiliation

Department of Electrical and Computer, Faculty of Engineering, Naresuan University, Pitsanulok,  Thailand 65000

Abstract

We propose a new mechanism for the stabilization of confined modes in lasers and semiconductor microcavities holding exciton-polariton condensates, with spatially uniform linear gain, cubic loss, and cubic self-focusing or defocusing nonlinearity. We demonstrated that the commonly known background instability driven by the linear gain can be suppressed by a combination of a harmonic-oscillator trapping potential and effective diffusion. Systematic numerical analysis of one- and two-dimensional (1D and 2D) versions of the model reveals a variety of stable modes, including stationary ones, breathers, and quasi-regular patterns filling the trapping area in the 1D case. In 2D, the analysis produces stationary modes, breathers, axisymmetric and rotating crescent-shaped vortices, stably rotating complexes built of up to 8 individual vortices, and, in addition, patterns featuring vortex turbulence. Existence boundaries for both 1D and 2D stationary modes are found in an exact analytical form, and an analytical approximation is developed for the full stationary states.
Keywords    Nonlinear optics; Spatial solitons; Laser theory; Microcavities


Title

Asst. Prof. Dr. Prawit Chumchu

Research Field
Telecommunication Network
Affiliation

Faculty of Engineering at Sriracha, Kasetsart University Sriracha Campus, Chonburi, Thailand 20230 


Title Informative Technology for Public Health Applications

Asst. Prof. Dr. Pichitpong Soontornpipit

Research Field
1. Decision support and artificial intelligent systems 
2. Data mining and database management 
3. Healthcare systems
4.  Biotelemedicine/ Biotelemedical systems
5. Wireless implantable devices
Affiliation

Department of Biostatistics, Faculty of Public Health, Mahidol University, Bangkok, Thailand  10400 

Abstract

The field of health technology and applications has many progresses in recent year with new concepts and new techniques. This session will be a platform for researchers to present their novel results in areas of informative technology applications in health such as Wireless Biotelemetry, Clinical Support Systems, Statistical Methods, Mathematical Models, Health Data Science, Artificial Intelligent, Database Management etc. Any interest submission can directly contact the Session Chair.

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