資料6-C

2016.10.31
23rd URSI-C Chair
Nobuyoshi Kikuma

Activity Report of URSI-C Committee- The 6th scientific workshop of the 23rd URSI-C in Japan-

1. Session title: "Fundamentals and Applications of Decoupling Circuits for Multiple
Antennas"
2. Convener: Dr. Toru Fukasawa, Mitsubishi Electric Corporation
3. Date/time: 13:20 - 16:20, June 16th, 2016
4. Venue: Hokkaido University (Kita-ku, Sapporo)
5. Registration fee: Free
6. Listed attendees: 26 persons
7. Local arrangement: Dr. Takashi Hikage (Hokkaido University)
8. Presentation:•13:20 - 13:30•13:30 - 14:10•14:10 - 14:50•14:50 - 15:00•15:00 - 15:40

Opening Remarks, Prof. Nobuyoshi Kikuma, Chair,Commission C of URSI-JNC (Nagoya Institute ofTechnology)"Decoupling Analysis and Circuits Design for Multi Beam
Antennas", Prof. Kenichi Kagoshima (Ibaraki University)"Broadband Design for Decoupling Circuits", Dr. Hidetoshi
Makimura (Mitsubishi Electric Corporation)
Coffee Break"Investigation for Decoupling Characteristics for MIMO
Antennas using Mutual Admittance", Dr. Hiroshi Sato(Panasonic Corporation)

資料6-C•15:40 - 16:20•16:20"Characteristics of Spatial Decoupling of MIMO Antennas for
Full-Duplex", Dr. Naoki Honma (Iwate University)
Closing

9. Reception: Attendees 16 persons at Kirin Beer Garden, Urban New build., Sapporo
10. The steering committee meeting took place from 12:00 to 13:00 on June 16th, 2016.
11. Concluding Remarks
The 6th workshop of 23rd URSI-C was held in Sapporo, a northern city in Japan.
The theme was “Fundamentals and Applications of Decoupling Circuits for Multiple
Antennas.” Lately, multiple antennas system has been commonly used for small radios.
When multiple antennas are set inside a small radio, coupling between antennas causes
some problems, such as degradations of efficiency and of correlation coefficient. The
decoupling circuits are one of the effective methods to overcome such problems. They
have been widely studied for about 10 years. The decoupling circuits do not only reduce
coupling between antennas, but also have many interesting features, such as
orthogonality between each radiation patterns for each eigenmodes, relation between
Q-factor and each eigenmodes, and so on. The decoupling circuits have both spatial
and circuit nature. Further, the technology has been utilized actual products of small
radios. They are interesting as a target of investigation and practical use.
In the workshop, Prof. Kagoshima explained vector analysis to reduce coupling
between dipole antennas, showing orthogonal characteristics of radiation patterns foreach eigenmodes, and relation between Q-factor and each eigenmodes. Dr. Makimura
proposed the method how to reduce coupling for wide frequency bandwidth between
small antennas which have steep frequency dependent characteristics. Dr. Sato showedthat combination of specific antenna configurations and circuits is effective to reduce
coupling between two antennas for multiple frequencies. Prof. Honma explained how
to reduce coupling between Tx and Rx antennas for Full-Duplex system. He has
proposed utilizing one specific modal beam to reduce the coupling. Theoretical andexperimental results were shown for some arrangements of antennas.
Participants made a lot of questions and discussions after the session and at theconvivial gathering. This workshop was successfully closed giving participants achance to discuss technology related to themselves.