Toshiro Kodera

I received the B.E., M.E. and Dr. Eng. from Kyoto Institute of Technology, Kyoto Japan, in 1996, 1998, and 2001, respectively. In this period, I developed some numerical program and devices using ferrite media. Numerical program is based on finite difference time domain (FDTD) method, and it is combined with gyrotropic dipole moment equation in time and space domain[16]. The most remarkable feature of this program is the inclusion of nonlinear property which can be seen in the ferrite material. The first version of the program was written for 1-D waveguide, and later it was extended to 2-D waveguide[15]. The second version (2D) was utilized to analyze the nonlinear property of magnetostaic waves, and the results were applied to some novel microwave devices such as magnetostatic wave mixer, and parametric amplifier *[22].
In 2001 I joined the Faculty of Engineering, Osaka Institute of Technology as a Lecturer. The five years in this university was mainly devoted to the education. Three or four courses and one student experiment for the daytime and night time course students per a week required most of the working time. Through these overwhelmed days, I developed full 3-D simulation program for a ferrite waveguide structure, and it was applied to some multi-functional microwave isolators [12][13][14] and a microwave receiver[11].
In 2005, I joined Wave Engineering Laboratories, ATR international, Kyoto Japan as an visiting researcher, and in 2006 I joined as a full-time researcher. In ATR, I engaged in R&D of GaAs MMICs for IEEE 802.15.3c Gbps wireless LAN system and high efficiency microwave power amplifier. In this period, I designed MMICs of (a) millimeter wave oscillator, (b) FSK demodulator, and (c) power amplifier for 60 GHz wireless LAN system. As the second topic, I designed a high efficiency power amplifier for WIMAX application *[12] *[13]. All of these were designed by purely commercial simulators (HFSS, ADS, VIRTUOSO).
In 2008, I applied the international job opening of Prof. Christophe Caloz, and joined Department of Electrical Engineering, Ecole Polytechnique of Montreal as a Research Associate. I worked for three research topics including :
Microwave radiative structure using magnetic material inspired by metamaterial concept
 Composite right left-handed (CRLH) is one of the well known response in the metamaterial. CRLH metamaterials exhibit a low-frequency left-handed band characterized by anti-parallel phase and group velocities (backward wave, double negative, or negative refractive index medium), and a high-frequency right-handed band characterized by parallel phase and group velocities (forward wave, double positive, or positive refractive index medium), with, under a so-called balanced condition, a unique gap-less non-zero group velocity transition frequency between these two bands where infinite guided-wavelength propagation occurs. Such a CRLH response, and in particular its unusual infinite-wavelength travelling-wave regime, had not been reported in other media and structures before their introduction and further developments.
 Unfortunately, CRLH metamaterial structures suffer of some weaknesses due to the fact that they consists of relatively complex lumped unit cells, where the required inductors (e.g. stub or spiral) and capacitors (MIM or interdigital) must be designed by extensive full-wave simulations. 
 In this work [9], I reported a novel uniform (without any complex lumped elements) ferrite-loaded open waveguide structure which exhibits an automatically balanced CRLH response. This novel response was applied to (a) dual-band leaky-wave antenna [8], (b) duplexer/diplexer integrated leaky-wave antenna [4], and (c) low profile magnetic monopole loop antenna [3].
Magnetic nanowire and its application to the millimeter wave devices

 Due to their low dielectric losses and low FMR (ferromagnetic resonance) 
linewidths, ferrites have been the major material used in the design of non-reciprocal microwave components. However, most ferrites suffer from a number of difficulties. They usually exhibit strongly temperature dependent properties, and are difficult to integrate into planar microwave circuits. Further, garnets and spinel ferrites generally require an external permanent magnet for operation. Ferromagnetic nanowire (FMNW) materials offer unprecedented possibilities for the conception of microwave devices, with new opportunities for dispersion engineering and for enhanced functionalities. Our group recently experimentally demonstrated [7] and theoretically modeled [6] the double FMR response. Also FMNW materials have been recently used to demonstrate microwave devices such as circulators *[8], isolators *[5], and antenna structure *[3].

Realization of perfect electro-magnetic conductor (PEMC) using magnetic material
 The realization of arbitrary PEMC boundaries by a grounded ferrite (GF) slab using Faraday rotation is introduced. This is the first practical realization of a PEMC to our knowledge. The key principle of the GF-PEMC boundary is the combination of Faraday rotation and reflection from the perfect electric conductor (PEC) of the ground plane. From this combined effect, arbitrary angles between the incident and reflected fields can be obtained at the surface of the slab, so as to achieve arbitrary PEMC conditions by superposition with the incident fields. 
 As a consequence of this research activity, we (Attieh Shavapour, Toshiro Kodera, and Christophe Caloz) received the 39th European Microwave Conference Young Engineers Prize 2009.

In March 2010, I joined the department of graduate school of science and engineering, Yamaguchi University, where I am now an non-tenure Associate Professor. I have one course for master student ( title of the course is “metamaterial”) and one course ( “optical and microwave engineering” ) for bachelor student. 
 Now I am trying to create the artificial gyrotropic property by the combination of nonlinear and passive components. Two referred conference papers [1][2] and one patent are submitted.