13 research outputs found
Ultra-Wideband Coplanar Waveguide to Asymmetric Coplanar Stripline Transition from DC to 165 GHz
AbstractThis paper presents an ultra-wideband coplanar waveguide (CPW)-to-asymmetric coplanar stripline (ACPS) transition based on aluminum nitride (AlN) substrate. The concepts of designing CPW, ACPS, and CPW-to-ACPS transition are explained. In order to suppress parasitic modes, vias going through AlN substrate are added along the ground traces. The signal trace is tapered out and chamfered to reduce the reflection caused by the termination of ground trace. The CPW-to-ACPS transition is designed, fabricated, and measured in a back-to-back configuration. The fabricated CPW-to-ACPS transition can provide a bandwidth of 165 GHz with an associated insertion loss of 3 dB.</jats:p
III-V Nanowire MOSFET High-Frequency Technology Platform
This thesis addresses the main challenges in using III-V nanowireMOSFETs for high-frequency applications by building a III-Vvertical nanowire MOSFET technology library. The initial devicelayout is designed, based on the assessment of the current III-V verticalnanowire MOSFET with state-of-the-art performance. The layout providesan option to scale device dimensions for the purpose of designing varioushigh-frequency circuits. The nanowire MOSFET device is described using1D transport theory, and modeled with a compact virtual source model.Device assessment is performed at high frequencies, where sidewall spaceroverlaps have been identified and mitigated in subsequent design iterations.In the final stage of the design, the device is simulated with fT > 500 GHz,and fmax > 700 GHz.Alongside the III-V vertical nanowire device technology platform, adedicated and adopted RF and mm-wave back-end-of-line (BEOL) hasbeen developed. Investigation into the transmission line parameters revealsa line attenuation of 0.5 dB/mm at 50 GHz, corresponding to state-ofthe-art values in many mm-wave integrated circuit technologies. Severalkey passive components have been characterized and modeled. The deviceinterface module - an interconnect via stack, is one of the prominentcomponents. Additionally, the approach is used to integrate ferroelectricMOS capacitors, in a unique setting where their ferroelectric behavior iscaptured at RF and mm-wave frequencies.Finally, circuits have been designed. A proof-of-concept circuit, designedand fabricated with III-V lateral nanowire MOSFETs and mm-wave BEOL, validates the accuracy of the BEOL models, and the circuit design. Thedevice scaling is shown to be reflected into circuit performance, in aunique device characterization through an amplifier noise-matched inputstage. Furthermore, vertical-nanowire-MOSFET-based circuits have beendesigned with passive feedback components that resonate with the devicegate-drain capacitance. The concept enables for device unilateralizationand gain boosting. The designed low-noise amplifiers have matching pointsindependent on the MOSFET gate length, based on capacitance balancebetween the intrinsic and extrinsic capacitance contributions, in a verticalgeometry. The proposed technology platform offers flexibility in device andcircuit design and provides novel III-V vertical nanowire MOSFET devicesand circuits as a viable option to future wireless communication systems
An overview of terahertz imaging with resonant tunneling diodes
Terahertz (THz) imaging is a rapidly growing application motivated by industrial demands including harmless (non-ionizing) security imaging, multilayer paint quality control within the automotive industry, insulating foam non-invasive testing in aerospace, and biomedical diagnostics. One of the key components in the imaging system is the source and detector. This paper gives a brief overview of room temperature THz transceiver technology for imaging applications based on the emerging resonant tunneling diode (RTD) devices. The reported results demonstrate that RTD technology is a very promising candidate to realize compact, low-cost THz imaging systems
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Integrated photonic devices for electromagnetic wave sensing, optical true time delay, and trace gas sensing
Investigations on how informative signals interact with optical light wave propagating in integrated photonic devices have been emerging research topics for various sensing and high-speed communication applications. These have become attractive research fields since integrated photonic devices offer unparalleled advantages such as high sensitivity, high-density integration, low power consumption, and great electromagnetic interference immunity. Among all available material platforms for integrated photonic devices, silicon is one of the ideal materials since silicon has excellent optical waveguides properties such as high transparency and high refractive index in optical communication wavelengths. These properties enable low loss and compact on-chip silicon photonic devices. Also, silicon photonic devices benefit from mature silicon-based semiconductor nanofabrication facilities; therefore, they can be fabricated with low cost. On the other hand, silicon photonic devices built on typical silicon dioxide-based silicon-on-insulator wafers can’t be operated beyond the wavelength of 3.5 μm due to high intrinsic mid-infrared absorption of silicon dioxide. Indium phosphide becomes an alternative candidate due to low optical loss. In addition, indium phosphide-based quantum cascade lasers provide narrowband tunable continuous-wave room-temperature emission in the entire mid-infrared spectral range from 3-11 μm which makes monolithically integrated devices possible. Wide varieties of photonics devices on both silicon and indium phosphide platforms have been demonstrated so far such as high-speed modulators, low loss waveguides, couplers, optical phased arrays, and sensors. In this dissertation, silicon integrated photonic devices for electromagnetic wave sensing and optical true time delay lines, as well as indium phosphide-based integrated photonic devices for trace gas sensing, are presented. This dissertation shows that integrated photonic devices are promising for high-performance sensing and novel communication applications.Electrical and Computer Engineerin
Wireless Terahertz Communications: Optoelectronic Devices and Signal Processing
Novel THz device concepts and signal processing schemes are introduced and experimentally confirmed. Record-high data rates are achieved with a simple envelope detector at the receiver. Moreover, a THz communication system using an optoelectronic receiver and a photonic local oscillator is shown for the first time, and a new class of devices for THz transmitters and receivers is investigated which enables a monolithic co-integration of THz components with advanced silicon photonic circuits