COMMISSION C: Radio Signals and Systems (November 2013 – October 2016)
Edited by Nobuyoshi Kikuma
C1. Ultra high definition digital television broadcasting
The research and development activities in the next-generation ultra-high definition
digital television (UHDTV) broadcasting are carried out by many industries andresearch institutes [Murayama, 2012][Nakamura, 2016]. The parameters for UHDTV
have been defined in ITU-R BT.2020-2 [ITU-R, 2015]. The number of pixels is7680×4320 in 8K UHDTV, which is 16 times larger than that of current HDTV. Highdynamic range (HDR) television system has been considered to improve the image
quality. The quantization levels for HDR is increasing to10-12 bits from 8 bits in thecurrent HDTV [Borer, 2015]. The required bit rate to accommodate UHDTV exceeds
300Mbps if the video codec for the current HDTV system is used. In contrast, thefrequency bandwidth for television broadcasting service is strictly limited. In theterrestrial television broadcasting in Japan, the frequency bandwidth available for one
program is the only 6 MHz. We need more efficient video encoding and digitaltransmission techniques for establishing UHDTV.
HEVC/H.265 standard [ISO/IEC, 2015-3][ITU-T, 2016] has been employed for theadvanced satellite broadcasting system [ARIB, 2014], whose test services has alreadybeen started in 2016. The more efficient video encoding scheme using adaptive use of
super-resolution technique has been proposed for the terrestrial broadcasting system[Matsuo, 2015]. The future video coding scheme will be standardized in 2020. Using thesophisticated video coding schemes, the required bitrate for 8K UHDTV can be reduced
to 50-70 Mbps.
In addition to the development of the efficient video encoding techniques, we require
the high frequency utilization efficiency digital transmission techniques. The digital
video broadcasting for the second generation terrestrial (DVB-T2) [DVB, 2015] employs
Multiple Input Single Output (MISO) transmission based on Alamouti's space-time
block code (STBC). The bit rate is up to 50 Mbps at the frequency bandwidth of 8 MHz.
To further improve the frequency efficiency, the use of Multiple-Input Multiple-Output(MIMO) techniques has been considered. NHK has proposed 2×2 MIMO broadcasting
using horizontal and vertical polarization antennae. As a modulation format, up to4096-level QAM (Quadrature Amplitude Modulation) is employed. The concatenateduse of LDPC (Low-Density Parity Check) code and BCH code, it can successfully reduce
the required Carrier to Noise Power Ratio (CNR). The available bit rate of the proposed
MIMO broadcasting system is up to 90 Mbps [Nakamura , 2016].
1

Alongside the video coding and digital transmission technologies, the layered divisionmultiplex (LDM) technique has been proposed for achieving multiple services at thesame frequency channel with different robustness [Zhang, 2016][Wu, 2012]. It provides
flexible and efficient use of the spectrum and backward compatibility property.
(M. Okada)
References
Kenichi Murayama [2012], “Large-capacity transmission technology for next-generation
digital terrestrial broadcasting in super hi-vision,” NHK STRL Technical R&D Report,
134, pp. 26-34.
Madoka Nakamura [2016], “R&D on transmission system for next-generationterrestrial broadcasting,” NHK STRL Technical R&D Report, 158, pp. 28-35.
Rec. ITU-R BT.2020-2 [2015], “Parameter Values for Ultra-High Definition Television
Systems for Production and International Programme Exchange”
T. Borer and A. Cotton [2015], “A “Display Independent” High Dynamic Range
Television System,” BBC Research & Development White Paper WHP 309.
ISO/IEC 23008-2 [2015], “Information Technology - High Efficiency Coding and Media
Delivery in Heterogeneous Environments – Part 2: High Efficiency Video Coding －”Rec. ITU-T H.265 [2016], “High Efficiency Video Coding”
ARIB [2014], “Transmission system for advanced wide band digital satellite
broadcasting,” ARIB STD-B44 Version 2.0.
Y. Matsuo, T. Misu, S. Iwamura and S. Sakaida [2015], “Video coding of 8K UHDTV by
HEVC/H.265 with spatio-gradational reduction and its restoration,” 2015 Picture
Coding Symposium (PCS), Cairns, QLD, 2015, pp. 40-44.
DVB document A122 [2015], “Frame structure channel coding and modulation for asecond generation digital terrestrial television broadcasting system (DVB-T2)”
L. Zhang, W. Li, Y. Wu, X. Wang, S. I. Park, H. M. Kim, J. Y. Lee, P. Angueira, and J.
Montalban [2016], “Layered-Division-Multiplexing: Theory and Practice,” IEEE
2

Transactions on Broadcasting, vol. 62, no. 1, pp. 216-232.
Y. Wu, B. Rong, K. Salehian, and G. Gagnon [2012], “Cloud Transmission: A New
Spectrum-Reuse Friendly Digital Terrestrial Broadcasting Transmission System,” IEEE
Transactions on Broadcasting, vol. 58, no. 3, pp. 329-337.

C2. Wireless Local Area Network (WLAN)
During November 2013-October 2016, one of the significant topics in WLAN related
issues was the release of the IEEE 802.11ac standard. The number of wireless LAN
devices with multi-user MIMO increased [Asai, 2014]. Although 802.11ad withhigh-throughput ability was also released, the number of devices conforming to thestandard has been relatively small. One of the reasons for this is the connection
distance. Improving the performance and extending the coverage of the system in the
millimeter-wave band are important issues for achieving the broad-band internet
connection anytime and everywhere [Sakaguchi, 2015]. Much research work has been
conducted including in the areas of diversity connection [Nagayama, 2016] andbeamforming [Takinami, 2016].
Radio-on-Fiber (RoF) is used for broadcasting repeater systems as a gap-filler in the
UHF band. It can adopt to OFDM based systems [Yu, 2014], and is an excellent
technique to enhance the coverage.

A RoF system can form a linear-cell where manytransmitters are placed along the fiber cable. It is also suitable as a wirelesscommunication system in transportation systems [Dat, 2016]. Research work for the
linear cell using a leaky coaxial cable with MIMO were also conducted to enhance thecapacity and to achieve reliable connection [Hou, 2015].
Positioning is another research topic. Since a lot of access points are already placed,
WLAN is a good infrastructure for positioning [Huang, 2016]. It is especially important
in indoor environments where signals from global positioning system (GPS) satellite
cannot be received [Yamamoto, 2015]. The position information can help with joining
and seamless handover to the 60 GHz WLAN cell.
(S. Tsukamoto)
References
Y. Asai, K. Ishihara, T. Murakami, R. Kudo, T. Ichikawa, Y. Takatori, M. Mizoguchi[2014], “Overview of Very High Throughput Wireless LAN Standard IEEE 802.11ac andExperimental Evaluation of Multiuser-MIMO Transmission,” IEICE Transactions on
3

Communications (Japanese Edition), Vol.J97-B No.1, pp.1-18.
K. Sakaguchi, E. M. Mohamed, H. Kusano, M. Mizukami, S. Miyamoto, R.E. Rezagah, K.
Takinami, K. Takahashi, N. Shirakata, H. Peng, T. Yamamoto, S. Nanba [2015],“Millimeter-Wave Wireless LAN and Its Extension toward 5G Heterogeneous
Networks,” IEICE Transactions on Communications, Vol.E98-B No.10, pp. 1932-1948.
T. Nagayama, S. Takeda, M. Umehira, K. Kagoshima, T. Miyajima [2016], “Improving
Performance by Countering Human Body Shadowing in 60GHz Band Wireless Systems
by Using Two Transmit and Two Receive Antennas,” IEICE Transactions on
Communications, Vol.E99-B No.2, pp. 422-429.
O.Takinami, H. Motozuka, T. Urushihara, M. Kobayashi, H. Takahashi, M. Irie, T.
Sakamoto, Y. Morishita, K. Miyanaga, T. Tsukizawa, N. Saito, N. Shirakata [2016], “A
60 GHz Hybrid Analog/Digital Beamforming Receiver with Interference Suppression for
Multiuser Gigabit/s Radio Access,” IEICE Transactions on Electronics, Vol.E99-C No.7,
pp. 856-865.
P. T. Dat, A. Kanno, N. Yamamoto, T. Kawanishi [2016], “5G transport networks: theneed for new technologies and standards,” IEEE Communications Magazine, vol. 54, no.
9, pp. 18-26.
X. Yu, Y. Yamao, M. Matsuura [2014], “EPWM-OFDM Signal Transmission against
Nonlinearities of E/O Converters in Radio over Fiber Channel,” IEICE Transactions on
Communications, Vol.E97-B No.2, pp. 484-494.
Y. Hou, S. Tsukamoto, S. Li, T. Higashino, K. Kobayashi, M. Okada [2015], “Capacity
Evaluation of MIMO Channel with One Leaky Coaxial Cable Used as Two Antennas
over Linear-cell Environments,” IEEE Transactions on Vehicular Technology, vol.PP,
no.99, pp.1-1.
M. Yamamoto, T. Ohtsuki [2015], “Power-Absorption-Based Model for Power
Compensation in WLAN Positioning Using Smartphone,” IEICE Transactions on
Communications, Vol.E98-B No.6, pp. 1125-1132.
Y. Huang, L.T. Hsu, Y. Gu, H. Wang, S. Kamijo [2016], “Database Calibration for4

Outdoor Wi-Fi Positioning System,” IEICE Transactions on Fundamentals ofElectronics, Communications and Computer Sciences, Vol.E99-A No.9, pp. 1683-1690.

C3. Microwave Passive Circuits
In relation to the development of recent wireless communication systems such as IoT(Internet of Things), M2M (Machine to Machine), and 5G (5th Generation), microwave
passive

circuits

with

high

performance

such

as

small-size,

low-loss,wideband/multi-wand, and tunable are strongly required. Several approaches and new
design techniques are currently investigated for their development purposes.
Novel directional couplers with waveguide- [Ishibashi, 2015][Kim, 2016] andplanar-type [Abe, 2016], and their applications have been reported. Microwave power
dividers have been also developed by using lumped-element circuits [Okada, 2015,2016], a planar structure [Wang, 2015], and the power combiner with MS line input andwaveguide output has been developed [Ravindra, 2015]. The reversed-phase coupler
with a very loose coupling can be obtained [Matsuda, 2016] using parallel ring-lines.
Moreover,severalplanarfiltersandresonators

have

been

developed

formillimeter-wave and THz applications [Shimizu, 2015][Chen, 2015, 2016], chipless
RFID tags [Sakai, 2016], and base stations [Ishizaki, 2015], and several types of BPF
and design methods have been reported [Tamura, 2016][Ohira, 2015, 2016].
Furthermore, tunable filters [Motoi, 2016][Wada, 2016] and the triplexer [Tani, 2016]
based on BPFs have been also reported.
Several SIW (Substrate Integrated Waveguide) components such as microstrip
line-waveguide transition [Uemichi, 2016], E-band filter [Kiumarsi, 2015], 60GHz band
BPF [Uemichi, 2015][Dong, 2016] have been proposed. These circuits are useful for
millimeter-wave and more high frequency regions. Multi-layer and LTCC circuitcomponents and their design methods have been also developed [Michishita,2015][Tajima, 2016].
Moreover, study and development of metamaterials including CRLH transmission
lines have been actively performed in these years. Several applications using thenegative order resonance of CRLH stub lines have been reported [Tanaka, 2015, 2016],
and its application to antenna system has been developed [Michishita, 2015][Ueda,
2016][Nagayama, 2016].
(T. Kawai)

5

References
H. Kiumarsi, K. Wasa, H. Ito, N. Ishihara, K. Masu [2015], “E-band Filters Based on
Substrate Integrated Waveguide Octagonal Cavities Loaded by Complementary
Split-Ring Resonators,” IEEE MTT-S Int’l Microwave Symposium, TU2D–3.
X. Wang, Z. Ma, I. Sakagami [2015], “A Compact and Harmonic Suppression Wilkinson
Power Divider with General Pi Type Structure,” IEEE MTT-S Int’l Microwave
Symposium, TU4D–5.
M. Ohira, T. Kato, Z. Ma [2015], “A Novel Microstrip Filter Structure Consisting ofTransversal Resonator Array and Its Fully Canonical Bandpass Filter Design,” IEEE
MTT-S Int’l Microwave Symposium, WE2D–1.
Y. Uemichi, O. Nukaga, K. Nakamura, X. Han, R. Hosono, N. Guan, S. Amakawa [2015],“Compact and Low-Loss Bandpass Filter Realized in Silica-Based Post-Wall Waveguidefor 60-GHz applications,” IEEE MTT-S Int’l Microwave Symposium, WEPK–4.
V. Ravindra, J. Hirokawa, Z. Miao, H. Saito [2015], “Cylindrical Cavity Microwave
Power Combiner with Microstrip Line Inputs and Rectangular Waveguide Output,”
IEEE MTT-S Int’l Microwave Symposium, WEPT–2.
T. Shimizu, Y. Kogami [2015], “Development of Low Loss Ka-Band Narrowband
Bandpass Filter using a Dual Mode Coplanar Type Circular Slot Resonator,” IEEE
MTT-S Int’l Microwave Symposium, THPD–3.
C. Chen, T. Anada, Z. Ma, S. Takeda, S. Greedy, T. Benson [2015], “Design ofPseudo-Elliptic Bandpass Filter using Higher-Order Modes of Photonic Crystal Point
Defect Cavity for Sub-Terahertz Bands,” IEEE MTT-S Int’l Microwave Symposium,
THPE–1.
T. Ishizaki, S. Nojiri, Y. Nakagawa [2015], “Basic Study on Novel Base-Station Filter
Using Artificial Dielectrics,” IEEE MTT-S Int’l Microwave Symposium, THPE–3.
S. Tanaka, H. Nishizawa, K. Takata, K. Saito [2015], “Dispersion-Engineered CRLH
Stub Resonator for Low Phase-Noise Oscillators,” IEEE MTT-S Int’l Microwave
Symposium, THPH–2.
6

N. Michishita, H. Morishita [2015], “Metamaterial Structures Composed of Multi-Layer
Ceramic Capacitors for Antenna Applications,” Proc. of the 45th European Microwave
Conference, EuMC/EuRAD01-3, pp.1327-1330.
H. Ishibashi, M. Kurihara, Y. Tahara, H. Yukawa, T. Owada, H. Miyashita [2015],“Waveguide Loop-Type Directional Coupler Using a Coupling Conductor with
Protuberances,” Proc. of the 45th European Microwave Conference, EuMCPoster02,
pp.1026-1029.
Y. Okada, T. Kawai, A. Enokihara [2015], “Wideband Lumped-Element Wilkinson
Power Dividers Using LC-Ladder Circuits,” Proc. of the 45th European Microwave
Conference, EuMC07-1, pp.1026-1029.
S. Tanaka, K. Mukaida, K. Takata [2015], “Compact Stub Resonators with Enhanced
Q-Factor Using Negative Order Resonance Modes of Non-Uniform CRLH Transmission
Lines,” IEICE Trans. on Electronics, Vol. E98-C, no.3, pp.252-259.
T. Shimizu, S. Kojima, Y. Kogami [2015], “Accurate Evaluation Technique of Complex
Permittivity for Low-Permittivity Dielectric Films Using a Cavity Resonator Method in
60-GHz Band,” IEEE Transactions on Microwave Theory and Techniques, Vol. 63, no.1,
pp.279-286.
T. Nagayama, A. Sanada [2015], “Planar Distributed Full-Tensor Anisotropic
Metamaterials

forTransformation

Electromagnetics,”

IEEE

Transactionson

Microwave Theory and Techniques, Vol. 63, no.12, pp.3851-3861.
T. Wada, T. Ogami, A. Horita, H. Obiya, M. Koshino, M. Kawashima, N. Nakajima[2016], “A New Tunable SAW Filter Circuit for Reconfigurable RF,” IEEE MTT-S Int’l
Microwave Symposium, TH1G–4.
M. Ohira, T. Kato, Z. Ma [2016], “Novel Microstrip Realization and Straightforward
Design of Fully Canonical Cul-de-Sac Coupling Bandpass Filters,” IEEE MTT-S Int’l
Microwave Symposium, WE2D–1.
T. Ueda, K. Ninomiya, K. Yoshida, T. Itoh [2016], “Design of Dispersion-free7

Phase-Shifting Non-reciprocity in Composite Right/Left Handed Metamaterials,” IEEE
MTT-S Int’l Microwave Symposium, TH2G–1.
Y. Uemichi, O. Nukaga, K. Nakamura, X. Han, R. Hosono, N. Guan [2016], “A Study on
the Broadband Transitions Between Microstrip Line and Post-Wall Waveguide in
E-Band,” Proc. of the 46th European Microwave Conference, EuMC01–4, pp.13-16.
C. Chen, T. Anada, S. Takeda, Z. Ma [2016], “Proposal and Theoretical Design of THz
Bandpass Filters Using Metallic Photonic Crystal Resonators,” Proc. of the 46th
European Microwave Conference, EuMC06–5, pp.116-119.
Y. Okada, T. Kawai, A. Enokihara [2016], “Compact Lumped-Element 5-Way Wilkinson
Power Divider with Broadband Operation,” Proc. of the 46th European Microwave
Conference, EuMC11–2, pp.202-205.
M. Abe, Y. Tahara, N. Yoneda, H. Takeda, T. Owada [2016], “Novel Tight Coupling andHigh Directivity λ/4 Partially-Narrowed and Slotted Coupled Line and its Application,”
Proc. of the 46th European Microwave Conference, EuMC11–5, pp.214-217.
F. Sakai, M. Makimoto, K. Wada [2016], “Multimode Stepped Impedance Resonatorsand their Application in Chipless RFID Tags,” Proc. of the 46th European Microwave
Conference, EuMC32–1, pp.604-607.
S. Tanaka, S. Koizumi, K. Saito [2016], “Compact Harmonic Tuning Circuits for Class-F
Amplifiers Using Negative Order Resonance Modes of CRLH Stub Lines,” Proc. of the
46th European Microwave Conference, EuMCPoster01, pp.1063-1066.
M. Tamura, K. Ichinose [2016], “Dual Band Filter with Quad-Mode Stripline Resonator,”
Proc. of the 46th European Microwave Conference, EuMCPoster02, pp.1159-1162.
K. Motoi, N. Oshima, M. Kitsunezuka, K. Kunihiro [2016], “A Band-Switchable andTunable Nested Bandpass Filter with Continuous 0.4–3GHz Coverage,” Proc. of the 46th
European Microwave Conference, EuMIC/EuMC05–1, pp.1421-1424.
T. Matsuda, T. Kawai, A. Enokihara [2016], “Parallel Ring-Line Rat-Race Circuit with
Very Loose Coupling Utilizing Short-Circuited Coupled Transmission Line,” Proc. of the8

2016 Asia Pacific Microwave Conference, WEPA41.
Y. Okada, T. Kawai, A. Enokihara [2016], “Design method of unequal Wilkinson power
divider using LC ladder circuits for multi-way power dividers,” Proc. of the 2016 Asia
Pacific Microwave Conference, TH1A–4.
Y. Uemichi, O. Nukaga, X. Han, R. Hosono, N. Guan, S. Amakawa [2016],“Characterization of 60-GHz SilicaBased Post-Wall Waveguide and Low-Loss Substrate
Dielectric,” Proc. of the 2016 Asia Pacific Microwave Conference, TH2A–3.
M. Ohira, T. Kato, Z. Ma [2016], “A Fully Canonical Bandpass Filter Design Using
Microstrip Transversal Resonator Array Configuration,” IEICE Trans. on Electronics,
Vol. E99-C, no.10, pp.1122-1129.
M. Ohira, K. Yamanaka, Z. Ma [2016], “A New Design Formula of Coupling Coefficient
between Antenna and Resonator for Efficient Design of Filtering Antenna,” IEICE
Trans. on Electronics, Vol. E99-C, no.7, pp.744-750.
K. Tani, K. Wada [2016], “Simulational Approach to Realize a Triplexer Based on
Bandpass Filters Using Wideband Resonators,” IEICE Trans. on Electronics, Vol.
E99-C, no.7, pp.751-760.
K. Dong, J. Mo, Y. He, Z. Ma, X. Yang [2016], “A Compact Millimeter-Wave Dual-Band
Bandpass Filter Using Substrate-Integrated Waveguide (SIW) Dual-Mode Cavities,”
IEICE Trans. on Electronics, Vol. E99-C, no.7, pp.761-765.
S. Tanaka, T. Katayose, H. Nishizawa, K. Hosoya, R. Ishikawa, K. Honjo [2016],“Miniaturization of Double Stub Resonators Using Lumped-Element Capacitors for
MMIC Applications,” IEICE Trans. on Electronics, Vol. E99-C, no.7, pp.830-836.
M. Abe, Y. Tahara, T. Owada, N. Yoneda, H. Miyashita [2016], “A Novel Directional
Coupler Loaded with Feedback Capacitances and Its Applications,” IEICE Trans. on
Electronics, Vol. E99-C, no.1, pp.85-94.
T. Tajima, H. Song, M. Yaita [2016], “Design and Analysis of LTCC-Integrated Planar
Microstrip-to-Waveguide Transition at 300 GHz,” IEEE Transactions on Microwave
9Theory and Techniques, Vol. 64, no.1, pp.106-114.
D. Kim, J．Hirokawa, M. Ando [2016], “Design of Waveguide Short-Slot Two-Plane
Couplers for One-Body 2-D Beam-Switching Butler Matrix Application,” IEEE
Transactions on Microwave Theory and Techniques, Vol. 64, no.3, pp.776-784.

C4. Wireless Interconnection for Microelectronics
The increase in capacity of wireless communication has been remarkable in recent
years. To meet these demands, various technologies such as massive MIMO
technologies [Lu, 2014] and short range MIMO technologies [Nishimori, 2011] [Hiraga,
2012] have been researched and developed. The orbital angular momentum (OAM)
multiplexing is one of the most promising technologies. [Mahmouli, 2013] demonstrates
transmission of 4-Gbps uncompressed video using OAM wireless channel in 2013. [Yan,2015] reports on an experimental measurement and analysis of multipath-induced
channel crosstalk effects in a mm-wave communications link using OAM at 28 GHz in2015. [Yan, 2016] reports an experimental demonstration of a 32-Gbps wireless linkusing OAM and polarization multiplexing with spiral phase plates in 2016.
[Cagliero, 2016] proposes a new general concept, the “OAM-link pattern,” which takes
into account the peculiar phase structure characterizing these waves in 2016. [Tian,
2016] propose three practical methods for beam axis detection and alignment, that is,
double parallelogram array method, double UCA method and single UCA method. D.
Lee, et al. present a simple but practical Rx antenna design method. Exploiting the factthat there are specific location sets with phase differences of 90 or 180 degrees, themethod allows each OAM mode to be received at its high SNR region. D. Lee, et al. also
introduce two methods to address the Rx SNR reduction issue by exploiting theproperty of a Gaussian beam generated by multiple uniform circular arrays and byusing a dielectric lens antenna.
(Y. Yamaguchi)
References
L. Lu, G. Y. Li, A. L. Swindlehurst, A. Ashikhmin, and R. Zhang [2014], “An Overview ofMassive MIMO: Benefits and Challenges,” IEEE Journal on Sel. Topics in Sig. Proc., vol.
8, no. 5, pp. 742-758.
K. Nishimori, N. Honma, T. Seki, and K. Hiraga [2011], “On the Transmission Method10for Short-Range MIMO Communication,” IEEE Trans. Veh. Tech., vol. 60. no. 3, pp.
1247-1251, Mar. 2011.
K. Hiraga, T. Seki, K. Nishimori, and K. Uehara [2012], “Effectiveness of Short-Range
MIMO Using Dual-Polarized Antenna,” IEICE Trans. Commun. vol. E95-B, no. 1, pp.
87-96.
F. E. Mahmouli and S. D. Walker [2013], “4Gbps uncompressed video transmission overa 60-GHz orbital angular momentum wireless channel,” IEEE Wireless Commun. Lett,
vol. 2, no. 2, pp. 223-226.
Y. Yan et al. [2015], “Experimental measurements of multipath-induced intra- andinter-channel crosstalk effects in a millimeter-wave communications link using
orbital-angular-momentum multiplexing,” in Proc. IEEE International Conference on
Communications (ICC), pp. 1370-1375.
Y. Yan et al. [2016], “32-Gbit/s 60-GHz millimeter-wave wireless communication using
orbital angular momentum and polarization multiplexing,” in Proc. IEEE International
Conference on Communications (ICC), pp. 1-6.
A. Cagliero, A. D. Vita, R. Gaffoglio, and B. Sacco [2016], “A new approach to the linkbudget concept for an OAM communication link,” IEEE Antennas and Wireless Propag.,
Lett., vol. 15, pp. 568-571.
H. Tian et al. [2016], “Beam axis detection and alignment for uniform circulararray-based orbital angular momentum wireless communication,” IET Commun., vol.
10, no. 1, pp. 44-49.

C5. Measurement Methods for Small Antennas
Measurement cables connected to small antennas for measurements sometimes causesignificant error. The influences of cables should be paid attention to carefully especiallyin case sizes of antennas or housings on which antennas mounted are small. This reportshows analysis method which can analyze the influence of measurement cables andmethods how to reduce the influences.
11

(1) Analysis method related to influences of measurement cables
Though it is well known fact that cables connected to antennas or housings tomeasure antenna characteristics sometimes cause errors, methods how to evaluate thesignificances of the errors has not been developed. Power radiated from an essential
antenna, which means an antenna in condition without measurement cable, is fed bybalanced mode on the measurement cable. On the other hand, unwanted radiation
power caused by connecting measurement cable is fed by unbalanced mode on themeasurement cable. The significance of the influence of the measurement cable can be
described by the ratio of the balanced and unbalanced modal conductances. Recently,
modal analysis method for a small antenna has been proposed [Yanagi, 2016] which canalso be applied to investigate the significance of the influence of measurement cable.
S-parameter method is applied to extract balanced and unbalanced conductances fromantenna impedance with measurement cable. The modal power radiated from antenna
with measurement cable connected can be analyzed by the modal ratio of balanced andunbalanced conductances [Yanagi , 2016].
(2) Measurement methods: S-parameter method
S-parameter method is one of the effective methods to reduce the influence ofmeasurement cables. Two ports of a network analyzer are connected signal line andground of an antenna. Balanced mode impedance which is equivalent to essential
antenna impedance without cable can be extracted numerically from full-2-port S
parameters. This method can reduce the influence of measurement cable significantly.
The method can be applied not only for impedance measurement but also for radiation
measurement. Other tips to improve measurement accuracy together with basis of themethod are summarized in [Sasamori, 2014].
(3) Measurement methods: Utilizing Fiber Optics
Application of fiber optics, instead of coaxial cable, to feed antenna can remove almost
completely the influence of the measurement cable. However, it requires additional
equipment which transform optical to RF (or RF to optical) signal. The equipment
causes error because it is usually made of metal [Yamaura, 2015]. The smaller size ofthe converter is important to improve measurement accuracy. In the article [Yamaura,
2015], combination of PV module to supply DC current and smaller PD module asconverter has been proposed. Total size of measurement equipment is reduced to
15*10mm and accurate measurement has been conducted.
Measurement system utilizing fiber-optics has also been applied to measure a small
antenna on a housing 3-dimensionally [Nguyen, 2014]. Further, RF signal source forpropagation characteristics measurement inside closed space has also been fed by
12fiber-optics to reduce influence of metallic cables [Yanagi, 2014].
(T. Fukasawa)
References
T. Yanagi, T. Fukasawa, H. Miyashita [2016], “Analysis of balanced and unbalanced
modal power ratio using S-parameter method,” IEICE Technical report, AP2015-169.
T. Sasamori, T. Fukasawa [2014], “S-Parameter Method and Its Application for Antenna
Measurements,” IEICE Trans. Commun., Vol.97-B, No.10, pp.2011-2021.
S. Yamaura, J. Nishioka, E. Haraguchi, T. Ando, T. Fukasawa, H. Miyashita [2015],“High-Accuracy Antenna Measurement Using a Small Photodiode Module,” IEICE
Technical report, AMT2015-01.
T. H. Nguyen, H. Morisihita [2014], “A Study on 3D Radiation Pattern Measurement of
Small Handset Antenna Using Optical Electric Field Sensor,” IEICE Technical report,
AMT2014-11.
T. Yanagi, T. Fukasawa, H. Miyashita, J. Abe, T. Tanabe, T. Yano, N. Inoue, S. Yoshida[2014], “Accurate Measurement of Propagation Characteristics in a Vacuum Circuit
Breaker by Using Fiber-optics,” IEICE Technical report, AMT2014-6.

C6. 300-GHz-Band Wireless Links
A terahertz (THz) transmitter capable of transmitting digital data at a rate exceeding
100 gigabits (= 0.1 terabit) per second over a single channel using the 300-GHz band has
been developed.

This technology enables data rates 10 times or more faster than thatoffered by the fifth-generation mobile networks (5G), expected to appear around 2020.
The THz band is a new and vast frequency resource expected to be used for future
ultrahigh-speed wireless communications. The research group has developed atransmitter that achieves a communication speed of 105 gigabits per second using thefrequency range from 290 GHz to 315 GHz. This range of frequencies are currently
unallocated but fall within the frequency range from 275 GHz to 450 GHz, whose usage
is to be discussed at the World Radiocommunication Conference (WRC) 2019 under theInternational Telecommunication Union Radiocommunication Section (ITU-R).
In 2016, the speed of a wireless link in the 300-GHz band was demonstrated with13

great enhancement by using quadrature amplitude modulation (QAM) [Katayama,
2016]. In 2017, six times higher per-channel data rate was shown, exceeding 100
gigabits per second for the first time as an integrated-circuit-based transmitter. At thisdata rate, the whole content on a DVD (digital versatile disk) can be transferred in a
fraction of a second.
A transmitter with 10 times higher transmission power than the previous version’s
were developed, which made the per-channel data rate above 100 Gbit/s at 300 GHz
possible. We usually talk about wireless data rates in megabits per second or gigabits
per second. But we are now approaching terabits per second using a plain simple single
communication channel. Fiber optics realized ultrahigh-speed wired links, and wirelesslinks have been left far behind. Terahertz could offer ultrahigh-speed links to satellites
as well, which can only be wireless. That could, in turn, significantly boost in-flight
network connection speeds, for example. Other possible applications include fast
download from contents servers to mobile devices and ultrafast wireless links between
base stations.
Another, completely new possibility offered by terahertz wireless is high-data-rate
minimum-latency communications. Optical fibers are made of glass and the speed oflight slows down in fibers. That makes fiber optics inadequate for applications requiring
real-time responses. Today, you must make a choice between ‘high data rate’ (fiber
optics) and ‘minimum latency’ (microwave links). You can’t have them both. But withterahertz wireless, we could have light-speed minimum-latency links supporting
fiber-optic data rates.
(M. Fujishima)
Reference
K. Katayama, K. Takano, S. Amakawa, S. Hara, A. Kasamatsu, K. Mizuno, K.
Takahashi, T. Yoshida, M. Fujishima [2016], “A 300GHz 40nm CMOS Transmitter with
32-QAM 17.5Gb/s/ch Capability over 6 Channels,” International Solid-State Circuits
Conference (ISSCC).

C7. Terahertz Technology
In this period, terahertz bands have been attracting great interest for highthroughput wireless communication systems such as FMCW RADAR, phase imaging,nondestructive material characterization and spectroscopy. In order to realize thesesystems, RF transceiver LSIs based on InP based HBT [Song, 2014], Si CMOS
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[Katayama, 2016] and SiGe BiCMOS [Sarmah, 2016] technologies have been reported.
Especially, transceiver LSIs using Si CMOS technologies have been demonstrated forhigh data rate communications [Wang, 2014], [Kang, 2014], and FMCW RADAR[Jaeschke, 2014], and spectroscopy [Han, 2013]. Thus, it is expected that Si CMOS
technologies

areformidablecost

effective

solutions

to

the

III-V

compoundsemiconductor ones.
Vector modulation methods are widely employed such as QPSK [Song, 2014], 32QAM[Katayama, 2016] and 64QAM [Takano, 2016] to increase the data rate.
(T. Yoshimasu)
References
K. Takano, K. Katayama, S. Amakawa, T. Yoshida, M. Fujishima [2016], “A 300-GHz
64-QAM CMOS transmitter with 21-Gb/s maximum per-channel data rate,” inEuropean Integrated Circuits Conf., pp.193-196.
N. Sarmah, J. Grzyb, K. Statnikov, S. Malz, P. Vazquez, W. Foerster, B. Heinemann, U.
Pfeiffer[2016],“A

Fully

Integrated

240-GHz

Direct-Conversion

Quadrature

Transmitter and Receiver Chipset in SiGe Technology,” IEEE Transaction on MTT,
Vol.64, No.2, PP.562-574.
K. Katayama, K. Takano, S. Amakawa, S. Hara, A. Kasamatsu, K. Mizuno, K.
Takahashi, T. Yoshida, M. Fujishima [2016], “A 300GHz 40nm CMOS Transmitter with
32-QAM 17.5Gb/s/ch Capability over 6 Channel,” in ISSCC Dig. Tech. Papers,
pp.342-343.
S. Kang, S. Thyagarajan, A. Niknejad [2014], “A 240 GHz wideband QPSK transmitterin 65 nm CMOS,” in Proc. of RF IC Symp., pp.353-356.
Ho-Jin Song, Jae-Young Kim, K. Ajito, N. Kukutsu, M. Yaita [2014], “50-Gb/s Direct
Conversion QPSK Modulator and Demodulator MMICs for Terahertz Communications
at 300 GHz,” IEEE Transactions on MTT, Vol.62, No.3, PP.600-609.
Z. Wang, P-Y Chiang, P. Nazari, C-C, Wang, Z. Chen, P. Heydari [2014], “A CMOS
210-GHz Fundamental Transceiver With OOK Modulation,” IEEE Journal of SSC,
Vol.49, No.3, pp.564-580.
T. Jaeschke, C. Bredendiek, N. Pohl [2014], “3D FMCW SAR imaging based on a 240
15

GHz SiGe transceiver chip with integrated antenna,” German Micro. Conf., pp.1-4,
R. Han, E. Afshari [2013], “A CMOS high-power broadband 260-GHz radiator array forspectroscopy,” IEEE Journal of SSC, Vol.48, no.12, pp.3090-3104.

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