Honjo KAZUHIKO (本城 和彦)

Offer Organization: Japan Society for the Promotion of Science, System Name: Grants-in-Aid for Scientific Research, Category: Grant-in-Aid for Scientific Research (B), Fund Type: -, Overall Grant Amount: - (direct: 9200000, indirect: 2760000)
Injection-locking of nonlinear oscillators to an external periodic forcing is a fundamental phenomenon which adjusts their frequencies to that of an external forcing. Such injection-locking enables to stabilize the frequency of the oscillator, and it has a long history and produces a large variety of applications. In our research, we develop a method for maximizing the frequency range of an external forcing sustaining the injection-locked mode (i.e., locking range or synchronization band), based on our newly developed optimization theory. As a case study of optimizing synchronizability, we design the input waveforms that maximize locking ranges in an injection-locked Class-E oscillator, by using our optimization theory. Further, we verify the optimality of these inputs through systematic numerical calculations and experiments.

Offer Organization: Japan Society for the Promotion of Science, System Name: Grants-in-Aid for Scientific Research, Category: Grant-in-Aid for Scientific Research (C), Fund Type: -, Overall Grant Amount: - (direct: 2700000, indirect: 810000)
An analytical model for multi-band antennas, realized with embedded lumped elements, has been derived. With the obtained formulae, an accurate design method to develop multi-band antennas for arbitrary bands over a short term is clarified. With the method, dual-band antennas for 2.5/5 GHz bands and 0.86/2 GHz band have been developed. In addition, frequency reconfigurable dual-band antennas are demonstrated. Furthermore, to design radiation patterns, the mode-transfer behavior in the frequency range was analyzed. With the analysis, antennas appropriate for MIMO applications were designed and fabricated. Under the favor of the designed unidirectional patterns, correlation coefficients in 2.5 and 5 GHz bands were shown to be reduced. The reduction is expected to improve the data transmission rate by 2 bit/Hz.

Offer Organization: Japan Society for the Promotion of Science, System Name: Grants-in-Aid for Scientific Research, Category: Grant-in-Aid for Scientific Research (C), Fund Type: competitive_research_funding, Overall Grant Amount: - (direct: 3900000, indirect: 1170000)
A novel approach for investigating the single-electron transistors (SETs) power gain functionality which is one of the most important features of active devices related with operation speed performance is proposed. Moreover, an evaluating method is also introduced to improve the SET power gain due to the influence of junction thickness. It is found that source junction thickness is the key factor affecting the power gain. This important finding is illustrated by taking into account the physical parameters of sample fabricated SET. According to proposed model, power gain can be improved by ramarkable amount of 39dB at frequencies up to THz regime by reducing 1.25nm in source junction thickness.