COMMISSION C : Radio Signals and Systems (Nov. '01 - Oct. '04)
C1. Radio Communication Systems
development activity in the field of radio communication systems, such as the
fourth-generation mobile/cellular radio
and wireless LAN systems has been still
Studies on OFDM or multicarrier transmission for general radio systems including the cellular and WLAN systems are also active. The PAPR (peak to average power ratio) and nonlinear distortion of power amplifier are important problems for this kind of systems, and some PAPR reduction schemes [Tomisato et al., 2003], [Fujii et al., 2003] and distortion compensation techniques [Hosono et al., 2002] were proposed.
Frequency domain equalization, which can be applied not only for multi-carrier but also for single carrier, is one of the interesting research fields in these three years. Some applications on those combining with diversity reception [Adachi et al., 2003] were investigated. Another remarkable field is interference cancellation. A unique adaptive algorithm for OFDM was proposed [Uesugi, 2003] and theoretical expressions of the performance of those for CDMA receivers were derived [Suzuki, 2003].
Adaptive antenna and MIMO studies have been very active. Capacity and performance of MIMO channel were measured in indoor environment [Sakaguchi et al., 2004], [Benjebbour et al., 2003]. Analog smart antennas and their theories were established [Ohira, 2003], and the adaptive beamforming algorithms were developed [Sun, 2004]. Some adaptive array techniques were investigated on OFDM systems to mitigate the interference due to delay spread longer than guard time [Hori et al., 2002], [Higuchi et al., 2004].
Wireless ad-hoc network [Ueda, 2002] and multi-hop radio system [Kishi, 2002] are other recently studied interesting issues in these research fields and several papers have been published.
Atarashi, H., S. Abeta and M. Sawahashi , Variable Spreading Factor-Orthogonal Frequency and Code Division Multiplexing (VSF-OFCDM) for Broadband Packet Wireless Access, IEICE Trans. on Commun.,Vol.E86-B, No.1, pp.291-299.
Kataoka, T., H. Taoka, K. Higuchi and M. Sawahashi , Adaptive antenna array-beam forming with simultaneous received path timing and DOA estimations based on two-dimensional power profile in broadband CDMA reverse link, Proc. ISSSE '04, Session 12-4, Linz.
Mikami, M. and T. Fujii , An antenna weight control method of downlink for adaptive array antenna at base station in DS-CDMA cellular system, IEICE Trans. Commun. (Japanese ed.), Vol. J87-B, No.9, pp.1174-1184.
Tomisato, S. and H. Suzuki , A peak reduction scheme based on control signal insertion for multi-carrier mobile communication systems, IEICE Trans. Commun., Vol. E86-B, No.6, pp.1910-1916.
Fujii,T. and M. Nakagawa , Peak power reduction for MC-CDMA using cluster assigned code selection, IEICE Trans. Commun., Vol. E86-B, No.9, pp.2637-2647.
Hosono, H., T. Hosokawa, T. Maeda, F. Maehara and F. Takahata , A compensating method based on recursive processing of nonlinear distortion for OFDM, IEICE Trans. Commun. (Japanese ed.), Vol. J85-B, No.1, pp.9-19.
Adachi, F., and T. Sao , Joint Antenna Diversity and Frequency-Domain Equalization for Multi-Rate MC-CDMA, IEICE Trans. Commun., Vol. E86-B, No.11, pp.3217-3224.
Uesugi, M. , An interference cancellation scheme for OFDM using adaptive algorithm, IEICE Trans. Commun., Vol.E86-B, No.11, pp.3182 – 3191.
Suzuki, T. , Analytical formulas for the overall performance of a linear parallel interference canceller for asynchronous CDMA, IEICE Trans. Commun. (Japanese ed.), Vol. J86-B, No.4, pp.630-644.
Sakaguchi, K., S. Ting and K. Araki , Initial measurement on MIMO eigenmode communication system, IEICE Trans. Commun. (Japanese ed.), Vol. J87-B, No.9, pp. 1454-1466.
Benjebbour, A. and S. Yoshida , Performance improvement of ordered successive detection with imperfect channel estimates for MIMO systems, IEICE Trans. Commun., Vol. J86-B, No.11, pp.3192-3199.
Ohira, T. , Reactance domain signal processing in parasite-array antennas, Asia-Pacific Microwave Conf., APMC2003, WD6-1, 1, pp.290-293, Seoul.
Sun, C., A. Hirata, T. Ohira and N. Karmakar , Fast beamforming of electronically steerable parasitic array radiator antennas: Theory and experiment, IEEE Trans. Antennas Propagat., Vo.52, No.7, pp.1819-1832.
Higuchi, K., and H. Sasaoka , Adaptive array suppressing inter symbol interference based on frequency spectrum in OFDM system, IEICE Trans. Commun. (Japanese ed.), Vol. J87-B, No.9, pp. 1222-1229.
Y., K. Tabata,
Ueda, T., S. Bandyopadhyay and K. Hasuike , An adaptive media access control protocol and system performance of wireless ad hoc network using smart antenna, IEICE Trans. Commun. (Japanese ed.), Vol. J85-B, No.12, pp. 2189-2197.
C2. Radio Circuits for
The third-generation mobile communications (3G) system, W-CDMA, started in May 2001. However it was only the system level launch. It was not enough miniaturization and cost for mass subsribers. Today, 2005, W-CDMA is becoming real consumer mobile communication system as the second-generation (2G) mobile communication system. To reduce parts count and materials cost, radio functionalities have been integrated rapidly toward System on Chip. For this objective, good technical harmonization of semiconductor (SiGe, EF-CMOS less than quarter micron rule), radio architecture (direct conversion receiver) and radio circuits (integrated VCO, high power amplifier) make a contribution [Itoh et al. 2004].
semiconductor techniques in
Regarding to radio
architecture, the 3G direct conversion receiver (DCR) was
firstly applied for the commercial model in
Regarding to circuit technique, the integrated VCO technique contribute miniaturization of mobile terminals. For stabilization of phase noise in wider frequency range, variable current cell was developed for the 3G utilization [Itoh 2002].
For next generation of radio communications like SDR (Software Defined Radio), broadband radio circuits were developed for re-configurable radio architecture [Araki 2004]. In an aspect of radio architecture analog based approach is very saturated. Most of RF circuits except power amplifiers can be integrated on LSI easily today. Under rapid evolution of sub-micron CMOS, research interests are dedicated to paradigm shift on radio architecture from analog to digital. Digital oriented RF architecture will be important research for the next several years.
Itoh, K., M. Uesugi,
Yoshida, H., T. Toyoda, I. Seto, O. Fujimoto, T. Arai, T. Itakura, H. Tsurumi , Fully Differential Direct-Conversion Receiver for W-CDMA Reducing DC-Offset Variation, IEICE Trans. Electron., Vol.E87-C No.6 pp.901-908.
Ugajin, M., A. Yamagishi, J. Kodate, M. Harada, T. Tsukahara , Design techniques for a 1-V operation Bluetooth RF transceiver, Proceedings of the IEEE 2004 Custom Integrated Circuits Conference, pp.393 - 400.
Komurasaki, H., T. Sano, T. Heima, K. Yamamoto, H. Wakada, Yasui, I., M. Ono, T. Miwa, H. Sato, T. Miki, N. Kato , A 1.8-V operation RF CMOS transceiver for 2.4-GHz-band GFSK applications, IEEE Journal of Solid-State Circuits, Vol.38, no. 5, pp.817 - 825.
Itoh, K., T. Yamaguchi, T. Katsura, K. Sadahiro, T. Ikushima, R. Hayashi, F. Ishizu, E. Taniguchi, T. Nishino, M. Shimozawa, N. Suematsu, T. Takagi, O. Ishida , Integrated even harmonic type direct conversion receiver for W-CDMA mobile terminals, 2002 IEEE MTT-S International Microwave Symposium Digest, pp.9-12.
Itoh, N., S. Ishizuka,  1200-MHz Fully Integrated VCO with "Turbo-Charger" Technique, IEICE Trans. Electron., Vol.E85-C, no.8, pp.1569-1576.
Araki, K., T. Nakagawa, Kawashema, M., K. Kobayashi, K. Akabane, H. Sheba, H. Hayashi,  Implementation and performance of a multi-band transceiver for software defined radio, Digest of 2004 IEEE Radio and Wireless Conference, pp.207 - 210
The research interests of RF integrated circuits (ICs) for wireless terminals are moving from single-band / single-mode to multi-band /multi-mode transceiver ICs. Recent wireless LAN ICs were developed as gCombo Chiph which covers 2.45GHz (IEEE 802.11b/g) and 5.2GHz (IEEE 802.11a) [McFarland, 2004], and Cellular phone ICs were developed as multi-band (0.8-2.1GHz) and multi-mode (GSM/PCS) chips [Kim, et al., 2004].
For the next generation systems (Beyond 3G or 4G), SDR (Software Defined Radio) and/or cognitive radio transceiver were discussed and the transceiver ICs for these application were reported [Madihian, 2002], [Araki, et al., 2004], [Abe, et al., 2001]. For these applications, a quadrature-mixer IC having 0.8-5.2GHz broad-band characteristic was reported [Kageyama, et al., 2004]. Direct conversion configuration became common for these Tx/Rx ICs [Nakajima, et al., 2004].
CMOS has been widely used for these ICs but SiGe still be used especially for narrow-band / wide dynamic range applications (i.e. Cellular phone/DTV) to achieve lower 1/f noise and higher saturation characteristics.
McFarland, W.J. , gWLAN system trends and the implications for WLAN RFICs,h 2004 IEEE RFIC symposium, MO3C-1.
Kim, Y., Y.Son, V.N.Parkhomenko, I. Hwang, K Nah, H.Lee, J.Cho, A.Sergeev and B.Park , gA GSM/EGSM/DCS/PCS direct conversion receiver with integrated synthesizer,h 2004 IEEE RFIC symposium, MO3B-1.
Madihian, M., gReconfigurable Si-RF Front-End Chips for Software Defined Radio,h 2002 Asia-Pacific Microwave Conference Proceeding, pp.1659-1663.
Araki K., T. Nakagawa, M. Kawashimi, K. Kobayashi, K. Akabane, H. Shiba. H. Hayashi  gImplementation and performance of a multi-band transceiver for software defined radio,h 2004 IEEE Radio and Wireless Conference (RAWCON), T3B.1.
Kageyama C., K. Nakajima, K. Tsutsumi, E. Taniguchi, M. Shimozawa, N. Suematsu , "0.8-5.2GHz band SiGe-MMIC Q-MIX for a multi-band multi-mode direct conversion receiver," 2004 IEEE Radio and Wireless Conference (RAWCON), T3B.2.
Nakajima K., T. Sugano, N. Suematsu , "A 5-GHz-band SiGe-MMIC direct quadrature modulator using a doubly stacked polyphase filter," 2004 IEEE Radio Frequency Integrated Circuits Symp. Dig. , TU3C-3.
Research activities for direction
of arrival (DOA) estimation in
As the trends of DOA estimation researches in these three years, implementation problems of DOA estimation techniques and their performance evaluation were highlighted. NTT began the field experiment of adaptive beamforming techniques by using DOA estimation results for the next generation base-station of the cellular phone in the spring of 2003. It was a promising event. Effects of fabrication error and mutual coupling of array elements were studied [Inoue, et al., 2001], [Inoue, et al., 2003]. To realize high resulution DOA estimation, several new array calibration techniques have been proposed; mutual coupling compensation by using generalized mode-vector [Yuan, et. al., 2004], the technique for array with coupled objects [Yamada, et al., 2004], and so forth. For progress in researches of DOA estimation algorithms, the following researches would be mentioned; New signal subspace method without eigen-decomposition [Xin, et al., 2004] that can successfully reduce computational burden without performance degradation, improved DOA tracking algorithm based on the signal subspace method [Kikuma, et al., 2004], DOA and angular spread estimation by using extended mode vectors [Hotta, et al., 2004], and so forth.
Moreover, it is one of
the features in
Furthermore, DOA estimation techniques as wireless propagation channel sounding for coming wireless systems, such as MIMO system [Takada, et al., 2001] and UWB system [Haneda, et al., 2003], were also extensively studied.
Ohira, T., K. Gyoda , "Hand-held microwave direction-of-arrival finder based on varactor-tuned analog aerial beamforming," 2001 Asia-Pacific Microwave Conference, vol.2, pp.585-588
Inoue, Y., K. Mori and H. Arai , "DOA error estimation using 2.6 GHz DBF array antenna," 2001 Asia-Pacific Microwave Conference, vol.2, pp.701 - 704.
Takada, J., K. Sakaguchi, K. Araki , "Development of high resolution MIMO channel sounder for the advanced modeling of wireless channels," 2001 Asia-Pacific Microwave Conference, vol.2, pp.563 - 568.
Haneda, K., J. Takada , "An application of SAGE algorithm for UWB propagation channel estimation," 2003 IEEE Conference on Ultra Wideband Systems and Technologies, pp. 483 - 487
Inoue, H., H. Arai , "Effect of mutual coupling and manufactural error of array for DOA estimation of ESPRIT algorithm," IEICE Trans. Commun. (Japanese Edition), Vol.J86-B, No.10, pp.2145-2152.
Xin, J., A. Sano , "Computationally efficient subspace-based method for direction-of-arrival estimation without eigendecomposition, "IEEE Trans. on Signal Processing, vol.52, no.4, pp.876 - 893
Matsumoto T., Y. Kuwahara, , g2D DOA estimation using beam steering antenna by the switched parasitic elements," International Symposium on Antennas and Propagation 2004 (ISAP2004), Vol.3, pp.916 - 919.
Yamada, H., R. Hara, Y. Yamaguchi , "Calibration of dipole array with reflector using method of images, "2004 International Symposium on Multi-Dimensional Mobile Communications, Vol.2, pp.660-664.
Tran, O., Y. Irie, S. Hara, Y. Nakaya, T. Toda, Y. Oishi , "A Beamforming Algorithm for ESPAR Antenna with RF-MEMS Variable Reactors, "IEICE Annual Conference, Fall, B-1-59
Hotta, H., N. Kikuma, K. Sakakibara, H. Hirayama , "Comparison of MUSIC algorithms using gradient- and integral-type mode vectors for direction of arrival and angular spread estimation, "IEICE Trans. Commun. (Japanese Edition), Vol.J87-B, no.9, pp.1414-1423.
Kikuma, N. , "Iterative DOA estimation using subspace tracking methods and adaptive beamforming, "IEICE Trans. Commun. (Japanese Edition), Vol.J87-B, no.9, pp.1149-1161.
Kim, M., K. Ichige, H. Arai, , "Implementation of FPGA Based Fast Unitary MUSIC DOA Estimator," IEICE Trans.Electronics, Vol.E87-C, No.9, pp.1485-1494.
Plapous, C., J. Cheng, E. Taillefer, A. Hirata, T. Ohira , "Reactance domain MUSIC algorithm for electronically steerable parasitic array radiator," IEEE Trans. on Antennas and Propagation, vol.52, no.12, pp.3257 – 3264
Yuan Q., Q.Chen, K.Sawaya , "Mutual coupling effect on performance of dataptive array antenna," International Symposium on Antennas and Propagation 2004 (ISAP2004), Vol.2, pp.625-628.
NTT DoCoMo commercially began
the FOMA service that was the third generation cellular phone system on
Oishi Y. et al., gHighly Efficient Power Amplifier for IMT-2000 BTS Equipment,h Fujitsu Scientific & Technical Journal, Vol. 38, No.2, pp.201-208., December 2002.
gEvolution of Power Amplifiers for Base station Application,h IEEE Topical
Workshop on Power Amplifiers for Wireless Communications 2003, Sept.2003. in
Space-time signal processing techniques have been playing an important role, particularly as demands for mobile communications increase. The space domain signal processing brought by the application of array antennas enables us to add one more dimension on the time domain signal processing. It results in further performance improvement under serious multipath fading environments in wireless communication systems.
Recently, in addition to the conventional concept of the space-time signal processing, some new concepts combining space-domain signal processing with time-domain coding so called as Space Time Block Code (STBC) have attracted much attention of researchers. Particularly in the last three years, many practical researches have been conducted towards its implementation and practical use in the real systems. For example, STBC is applied to multi-carrier systems that are employed in digital broadcastings, wireless local area networks (WLAN) and so on. In these systems, Orthogonal Frequency Division Multiplexing (OFDM) is combined with STBC by using multiple antennas to obtain the diversity gain effectively in rich multipath fading environments [X.N.Tran et al, 2005],[M. Fujii, 2003].
Multi-carrier systems such as OFDM, Multi-Carrier Code Division Multiple Access (MC-CDMA) are widely paid attention for the applications in mobile systems. Naturally, these schemes are extended over the space domain in order to obtain further performance improvement. However, in these systems, space time signal processing causes heavy computational load. Some researches try to reduce the complexity by using a frequency-domain signal processing technique [F. Adachi et al, 2003], [T. Itagaki et al, 2004].
Non-linear signal processing techniques applied on the space- and time-domain signal processing yields quite interesting new features. Some of such applications allows us to demodulate Direct-Sequence Spread Spectrum (DS/SS) signals without any knowledge of the signal even the spreading code [Y. Kamiya et al, 2001], [Y. Kamiya et al, 2003]. It demodulate DS/SS signal asynchronously and blindly while it accomplishes the equalization of delayed signals and beamforming, simultaneously. These features are advantageous because of the following reason. In DS/SS systems, conventionally, space-time signal processors require a training sequence inserted in communication signals. In other words, the processors require the bit-timing synchronization. However, it should be noted that this fact implies that the processors cannot perform the signal processing until the synchronization is acquired even though the space-time signal processing is performed to enable the demodulation under severe environments. These new configurations based on non-linear signal processing solve this paradoxical problem.
Although space-time signal processing improves the performance of the receiver significantly, it causes large-scale configuration due to the usage of multiple antennas. Multiple antennas results in multiple RF front-ends and A/D converters. In order for reducing the hardware complexity of the space-time signal processing, combination with ESPAR antenna is attractive solution. ESPAR antenna achieves beamforming in the analog domain so that it enables us to reduce the RF front-ends and A/D converters. Its adaptive control scheme has been proposed in [J. Cheng, 2001]. After that, it is combined with the above-mentioned non-linear signal processing schemes [Y. Kamiya et al, 2003].
Tran, X. N., T. Fujino and Y. Karasawa  gSpatio-Temporal Equalization for Space-Time Block Coded Transmission over Frequency Selective Fading Channel with Co-channel Interference,h IEICE Trans., Fundamentals, Vol.E88-A No.3 pp.660-668.
M. Fujii , gBeamspace-Time Transmit Diversity for Time-Domain Spreading OFDM-CDM Systems,h IEICE Trans., Commun., Vol. E86-B, No. 1.
Adachi F. and T. Sao , gJoint Antenna Diversity and Frequency-Domain Equalization for Multi-Rate MC-CDMA,h IEICE Trans., Commun., Vol. E86-B, No. 11.
Itagaki T. and F. Adachi  gJoint Frequency-Domain Equalization and Antenna Diversity Combining for Orthogonal Multicode DS-CDMA Signal Transmissions in a Frequency-Selective Fading Channel,h IEICE Trans., Commun., Vol.E87-B No.7, pp.1954-1963
Kamiya Y., S. Denno, Y. Mizuguchi, M. Katayama, A. Ogawa , Y. Karasawa: gNovel Configuration of CMA Adaptive Array for Beamforming, Equalization and Despreading of SS signals,h IEICE Trans., Fundamentals, Vol. J85-A, No. 1, pp. 31-41.
Kamiya Y., K. Ochiai, Y. Karasawa , gA Multistage Blind Adaptive Array Antenna for Multiuser Signal Detection in Asynchronous SS Sysmtes,h IEICE Transactions on Communications, Vol. E86-B. No. 8, pp. 2414-2424.
Cheng J., Y. Kamiya, and T. Ohira , gAdaptive beamforming of ESPAR antenna based on steepest gradient algorithm,h IEICE Transactions on Communications, Vol. E84-B, No. 7, pp.1790-1800.
Extensive studies on left-handed materials and applications have been carried out. Zeroth-order resonance in the composite right/left-handed transmission line has been studied [Sanada et al., 2003], and radiation characteristics of the zeroth-order resonator have further been studied for antenna applications [Sanada et al., 2004]. The characteristics of the right/left-handed transmission line have been theoretically summarized in [Sanada et al., 2004] and purely distributed negative refractive index lenses have also been demonstrated experimentally [Sanada et al, 2004] based on the 2-dimensional planar composite right/left-handed transmission line structure. Wideband planar backward couplers have also been proposed [Caloz et al., 2004]. In addition, novel microwave devices and antennas have been proposed and demonstrated; nonreciprocal left-handed transmission lines using ferrite substrates [Tsutsumi et al., 2004], novel via-free planar left-handed transmission line structure and antenna applications [Sanada, et al., 2004], left handed transmission lines using gyrator [Okubo et al., 2004], ferrite left-handed transmission line circulators [Tsutsumi et al., 2004], ferrite loaded left-handed waveguides [Ueda et al., 2004], compact multi-layered left-handed transmission line structures [Horii et al., 2004], novel planar left-handed transmission line structures using enhanced capacitors with built-in shunt inductor on the ground plane [Sahara et al., 2004], planar left-handed dual-band branch line couplers [Matsunaga et al., 2004], and 2D beam scanning left-handed leaky-wave antennas [Aso et al., 2004].
Besides the left-handed materials, right-handed metamaterials and periodic PBG/EBG structures have also been studied. Compact artificial dielectric resonators with spurious suppression have been demonstrated [Awai et al., 2004] exploiting its huge permittivity and resonant mode control functionality. Loss study of artificial dielectrics based on metal strips has also been carried out [Kubo et al., 2004]. In optics frequency, studies on PBG structures [Hangyo et al, 2004] and optical fiber applications of PBG structures [Koshiba 2004] have successfully been carried out. In addition, photonic crystals in THz regions have been demonstrated [Takeda 2004] as well as in microwave regions [Kawasaki 2004].
Sanada, A., C. Caloz, and T. Itoh , gNovel zeroth-order resonance in composite right/left-handed transmission line resonators,h 2003 Asia-Pacific Microwave Conference Proceedings, pp. 1588-1591.
Sanada, A., M. Kimura, I. Awai, H. Kubo, C. Caloz, and T. Itoh , gA planar zeroth-order resonator antenna using a left-handed transmission line,h 2004 European Microwave Conference Proceedings, Amsterdam, pp. 1342-1344.
Sanada, A., C. Caloz, and T. Itoh , gCharacteristics of the Composite Right/Left-Handed Transmission Lines,h IEEE Microwave and Wireless Component Letters, Vol. 14, No.2, pp. 68-70.
Sanada, A. C. Caloz, and T. Itoh , gPlanar Distributed Structures with Negative Refractive Index,h IEEE Trans. on Microwave Theory and Techniques, Vol. 52, No. 4, pp. 1252-1263.
Caloz, C., A. Sanada, and T. Itoh , gA novel composite right/left-handed coupled-line directional coupler with arbitrary coupling level and broad bandwidth,h IEEE Trans. on Microwave Theory and Techniques, Vol.52, No. 3, pp. 980-992.
Tsutsumi, M., and T. Ueda, , gNonreciprocal left handed transmission characteristics in ferrite microstrip lines,h Transactions on Electronics, IEICE, VOL.J87-C No.2, pp. 274-275.
Sanada, A., K. Murakami, S. Aso, H. Kubo, and I. Awai , gA via-free microstrip left-handed transmission line,h IEEE International Microwave Symposium Digest, pp. 301-304.
Okubo, K., and M. Tsutsumi , gOn a left handed transmission line using gyrator,h Proceedings of the 2004 IEICE Society Conference, C-2-56, p. 72.
Tsutsumi, M., and T. Ueda , gA ferrite left-handed transmission line circulator,h Proceedings of the 2004 IEICE Society Conference, C-2-57, p. 73.
Ueda, T., and M. Tsutsumi , gLeft-handed transmission characteristics in waveguides periodically filled with ferrite,h Proceedings of the 2004 IEICE Society Conference, C-2-58, p. 74.
Horii, Y., C. Caloz, and T. Itoh , gCompact multi-layered Left-handed transmission line,h Proceedings of the 2004 IEICE Society Conference, C-2-59, p. 75.
Sahara, S., S. Aso, A. Sanada, and H. Kubo , gOn a novel left-handed transmission line using enhanced capacitors with built-in shunt inductor on the ground plane,h Proceedings of the 2004 IEICE Society Conference, C-2-60, p. 76.
Matsunaga, N., A. Sanada, and H. Kubo , gDesign of dual band transmission lines using composite right/left-handed transmission lines,h Proceedings of the 2004 IEICE Society Conference, C-2-61, p. 77.
Aso, S., A. Sanada, and H. Kubo , gOn a 2D beam scanning using left-handed leaky wave antennas,h Proceedings of the 2004 IEICE Society Conference, C-2-106, p. 122.
Kubo, H., A. Sanada., and I. Awai , gCharacteristics of artificial dielectric composed of metal strips and the application,h Technical Report of IEICE, MW2004-92, pp. 145-150.
Hangyo, M., F. Miyamaru, M. Tanaka, M. Tani, , gPhotonic crystals probed by terahertz time domain spectroscopy,h Technical Report of IEICE, MW2004-95, pp. 165-170.
Koshiba, M. , gFundamental properties of photonic crystal fibers: holey fibers and photonic band-gap fibers,h Technical Report of IEICE, MW2004-93, pp. 151-158.
Takeda, M. W , gPhotonic crystals in THz region,h Technical Report of IEICE, MW2004-94, pp. 159-164.
ATR Wave Engineering Laboratories
ATR Wave Engineering Laboratories
This work is part of "Research and development of ultra-high speed giga-bit rate wireless LAN systems" supported by National Institute of Information and Communication Technology (NICT).