2010 IEEE MTT-S International Microwave Symposium Technical Program

Session: WE2E	Emerging Technologies for mm to Submm systems
Chair:	Imran Mehdi, NASA JPL
Co-Chair:	H. Alfred Hung, Army Research Lab
Abstract:	This session focuses on emerging technologies to the THz frequency range. Novel waveguide structures and transitions, imaging and modulation techniques, and THz sources and detectors will be presented.

WE2E-1	10-Gbit/s QPSK Modulator and Demodulator for a 120-GHz-band Wireless Link
10:10 AM-10:30 AM	H. Takahashi¹, T. Kosugi², A. Hirata¹, K. Murata², N. Kukutsu¹, ¹Nippon Telegraph and Telephone Corporation, Atsugi, Japan, ²Nippon Telegraph and Telephone Corporation, Atsugi, Japan
(1089)	This paper describes a 120-GHz-band quadrature phase shift keying (QPSK) modulator and demodulator fabricated on microwave monolithic integrated circuits (MMICs) for a 10-Gbit/s wireless link. The MMICs were fabricated using 0.1-μm-gate InP HEMTs and coplanar waveguides. The direct-conversion modulator consists of hybrid couplers, gain-control amplifiers, and combiners. The delay demodulator has a 200-ps delay line, distribution amplifiers, a voltage-controlled phase shifter, and detectors. The modulator and demodulator MMICs were mounted in WR-8 waveguide modules to evaluate the characteristics of 10-Gbit/s transmission. The bit error rate (BER) for 10-Gbit/s pseudorandom binary sequence (PRBS) data was smaller than 1E-10.

WE2E-2	High-phase-resolution 77-GHz-band radar module for near-field millimeter-wave imaging
10:30 AM-10:50 AM	S. Mochizuki¹, S. Oka², H. Togo¹, N. Kukutsu¹, ¹NTT Microsystem Integration Laboratories, Atsugi, Japan, ²NTT Access Network Service Systems Laboratories, Tsukuba, Japan
(1412)	Near-field millimeter-wave (MMW) imaging is a unique approach for inspecting cracks in covered concrete surfaces to assess the deterioration of concrete structures. We have developed a 77-GHz-band radar module with in-phase and quadrature detection which is superior to measuring both of the amplitude and phase of MMW in a near-field range. A monostatic radar system is hybrid integrated into the module with a constant-width antipodal tapered slot antenna with an antenna gain of 14.5 dBi which is connected to a microstrip-line coupler with an isolation of higher than 26 dB using a leakage cancellation technique. In distance measurements in free space, the phase resolution is less than 8 degrees corresponding to the distance resolution of smaller than 0.01 mm, which is high enough to distinguish MMW signals scattered by the cracks from multiple reflection of the concrete surfaces and inside aggregates.

WE2E-3	Waveguide Transition to Feed a Fully PCB Integrated Dielectric Rod Antenna
10:50 AM-11:00 AM	F. Poprawa¹, A. Zanati¹, A. Ziroff¹, F. Ellinger², ¹Siemens AG, Munich, Germany, ²Dresden University of Technology, Dresden, Germany
(1507)	A microstrip line-to-circular waveguide transition is described which operates at a nominal design frequency of 77 GHz. In order to improve the transmission characteristics, an additional periodically structured shield is used. The transition is capable of exciting a dielectric rod antenna, thus enabling the realization of radar modules on a PCB substrate with a dielectric rod antenna interface.

WE2E-4	Hollow-core Electromagnetic Band Gap (EBG) Waveguide Fabricated by Rapid Prototyping for Low-loss Terahertz Guiding
11:00 AM-11:10 AM	Z. Wu, W. Ng, M. Gehm, H. Xin, University of Arizona, Tucson, United States
(1615)	An all-dielectric THz waveguide has been designed, fabricated and characterized. The design is based on electromagnetic band gap (EBG) structures, and the fabrication is implemented with polymer-jetting rapid prototyping method. Measurement results show good consistency with design simulations. As an initial example, a waveguide with low propagation loss of 0.03 dB/mm at 105 GHz is demonstrated.

WE2E-5	Monolithic 28.3 THz Thermal Image Sensor Incorporating 0.18-um CMOS Foundry
11:10 AM-11:30 AM	S. Yang¹, L. Su¹, I. Huang¹, C. Ting², C. C. Tzuang¹, ¹National Taiwan University, Taipei, Taiwan, ²University of Houston, Houston, United States
(1747)	This paper presents a fully monolithic approach to the design and fabrication of THz CMOS image sensor operating at 28.3 THz using the mass-producible 0.18-um 1P6M CMOS foundry. The CMOS sensor consists of antenna-coupled transducer, linearly transforming the intercepted THz (terahertz) electromagnetic energy into voltage representation. The THz image sensor adopts PTAT (Proportional To Absolute Temperature) sensing circuit configureation. The THz thermal sensor occupies 68 um × 42 um chip area. A 500 um-thick CMOS test chip of chip size 700 um × 700 um was scanned by a THz laser beam of 26 um diameter with built-in THz thermal sensors. The scanned THz thermal image of the test chip was compared with the die photo, clearly demonstrating the validity of the design concept of the proposed THz image sensor. The responsivity measured by considering the entire test chip is 6 V/W.

WE2E-6	Waveguide Design for Bi-Modal Operation of THz Quantum Cascade Lasers
11:30 AM-11:50 AM	S. Razavipour¹, S. Fathololoumi¹, G. Z. Rafi¹, D. Ban¹, S. Safavi-Naeini¹, S. R. Laframboise², Z. Wasilewski², H. Liu², ¹University of Waterloo, Waterloo, Canada, ²National Research Council of Canada, Ottawa, Canada
(1621)	The design and fabrication of a bi-modal semi-insulating surface-plasmon waveguide for a quantum cascade laser emitting at 3.75 THz is presented. Different transverse modes are excited under different electric current injection due to their different overlapping with the laterally nonuniform gain profile in the active region. HFSS and COMSOL program are used to simulate the near/far field and loss for various waveguide structures, respectively. It is found that a 150 m wide surface-plasmon waveguide allows either co-excitation or selective excitation of the first two transverse modes. The total optical loss (i.e., the combination of waveguide and mirror loss) is found below 20 cm-1. An electrically controllable dynamic beam pattern steering is predicted. The near and far field measurements of a fabricated quantum cascade laser device confirm the theoretical results. The dynamic switching of far-field beam pattern by an angle of 25° is observed when the current density changes.

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