Amin Arbabian

Stanford University, Stanford, California, United States

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Publications (28)27.26 Total impact

  • A. Arbabian · N. Dolatsha · N. Saiz
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    ABSTRACT: A millimetre-wave interconnect on a very low-cost plastic waveguide is proposed for applications in terabit per second wireline links. Simultaneous utilisation of the two fundamental and polarisation-orthogonal degenerate Ex11 and Ey11 waveguide modes doubles the capacity of a single line without sacrificing robustness or adding implementation cost and complexity. A prototype of the structure has been fabricated in high-density polyethylene (HDPE) fed with dipole/slot coupling structures on Rogers RO6006, and operates at frequencies of about 75 GHz with an aggregate 3 dB bandwidth exceeding 60 GHz.
    No preview · Article · Aug 2015 · Electronics Letters
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    ABSTRACT: A first proof-of-concept mm-sized implantable device using ultrasonic power transfer and a hybrid bi-directional data communication link is presented. Ultrasonic power transfer enables miniaturization of the implant and operation deep inside the body, while still achieving safe and high power levels (100 $mu$W to a few mWs) required for most implant applications. The current implant prototype measures 4 mm$times $7.8 mm and is comprised of a piezoelectric receiver, an IC designed in 65 nm CMOS process and an off-chip antenna. The IC can support a maximum DC load of 100$mu$W for an incident acoustic intensity that is $sim $ 5% of the FDA diagnostic limit. This demonstrates the feasibility of providing further higher available DC power, potentially opening up new implant applications. The proposed hybrid bi-directional data link consists of ultrasonic downlink and RF uplink. Falling edge of the ultrasound input is detected as downlink data. The implant transmits an ultra-wideband (UWB) pulse sequence as uplink data, demonstrating capability of implementing an energy-efficient M-ary PPM transmitter in the future.
    No preview · Article · Aug 2015 · IEEE Journal of Solid-State Circuits
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    ABSTRACT: A wireless-powered pad-less single-chip radio is implemented in 65 nm CMOS for applications in Internet of Things (IoT) and wireless tagging. This fully-self-sufficient mm-wave radio has no pads or external components (e.g., power supply), and the entire radio is a single chip with dimensions of 3.7 mm by 1.2 mm. To provide multi-access, and to mitigate interference, it uses two separate mm-wave bands for RX/TX and integrates both antennas to provide a measured communication range of 50 cm. The transmitter uses a modified Multipulse Pulse Position Modulation (MPPM) with 2 GHz of bandwidth on a 60 GHz carrier to communicate the data sequence as well as the local timing reference. The entire system operates with standby harvested power below 1.5 µW and achieves an aggregate data rate > 12 Mbps.
    No preview · Article · Apr 2015 · IEEE Journal of Solid-State Circuits
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    ABSTRACT: A radio frequency (RF)/ultrasound hybrid imaging system using airborne capacitive micromachined ultrasonic transducers (CMUTs) is proposed for the remote detection of embedded objects in highly dispersive media (e.g., water, soil, and tissue). RF excitation provides permittivity contrast, and ultra-sensitive airborne-ultrasound detection measures thermoacoustic-generated acoustic waves that initiate at the boundaries of the embedded target, go through the medium-air interface, and finally reach the transducer. Vented wideband CMUTs interface to 0.18 μm CMOS low-noise amplifiers to provide displacement detection sensitivity of 1.3 pm at the transducer surface. The carefully designed vented CMUT structure provides a fractional bandwidth of 3.5% utilizing the squeeze-film damping of the air in the cavity.
    No preview · Article · Feb 2015 · Applied Physics Letters
  • Nicholas Saiz · Nemat Dolatsha · Amin Arbabian
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    ABSTRACT: In this paper, a 135 GHz antenna-in-package (AiP) transmitter with high equivalent isotropic radiated power (EIRP) is presented. The radiating element is realized by a dielectric rod antenna fed by a planar Yagi-like electric dipole. A SiGe transmitter composed of an active balun, 8× frequency multiplier and a power amplifier is mounted on the AiP. The operating frequency of the system is 125-140 GHz. The measured EIRP at 135 GHz is 15.6 dBm and the DC power consumption is 366 mW.
    No preview · Conference Paper · Sep 2014
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    ABSTRACT: A first proof-of-concept mm-sized implant based on ultrasonic power transfer and RF uplink data transmission is presented. The prototype consists of a 1 mm × 1 mm piezoelectric receiver, a 1 mm × 2 mm chip designed in 65 nm CMOS and a 2.5 mm × 2.5 mm off-chip antenna, and operates through 3 cm of chicken meat which emulates human tissue. The implant supports a DC load power of 100 μW allowing for high-power applications. It also transmits consecutive UWB pulse sequences activated by the ultrasonic downlink data path, demonstrating sufficient power for an Mary PPM transmitter in uplink.
    No preview · Conference Paper · Sep 2014
  • Hao Nan · Tzu-Chieh Chou · Amin Arbabian
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    ABSTRACT: Microwave-induced thermoacoustic (TA) imaging combines the soft-tissue dielectric contrast of microwave excitation with the resolution of ultrasound for the goal of a safe, high resolution, and possibly portable imaging technique. However, the hybrid nature of this method introduces new image-reconstruction challenges in enabling sufficient accuracy and segmentation. In this paper, we propose a segmentation technique based on the polarity characteristic of TA signals. A wavelet analysis based method is proposed to identify reflection artifacts as well. The time-frequency feature of the signal is used to assist differentiating artifacts. Ex vivo verification with experimental data is also provided.
    No preview · Article · Aug 2014
  • Hao Nan · Amin Arbabian
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    ABSTRACT: Microwave-induced thermoacoustic (TA) imaging combines the dielectric contrast of microwave imaging with the resolution of ultrasound imaging. Prior studies have only focused on time-domain techniques with short but powerful microwave pulses that require a peak output power in excess of several kilowatts to achieve sufficient signal-to-noise ratio (SNR). This poses safety concerns as well as to render the imager expensive and bulky with requiring a large vacuum radio frequency source. Here, we propose and demonstrate a coherent stepped-frequency continuous-wave (SFCW) technique for TA imaging which enables substantial improvements in SNR and consequently a reduction in peak power requirements for the imager. Constructive and destructive interferences between TA signals are observed and explained. Full coherency across microwave and acoustic domains, in the thermo-elastic response, is experimentally verified and this enables demonstration of coherent SFCW microwave-induced TA imaging. Compared to the pulsed technique, an improvement of 17 dB in SNR is demonstrated.
    No preview · Article · Jun 2014 · Applied Physics Letters
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    ABSTRACT: A wireless-powered pad-less single-chip dual-band mm-wave passive radio is implemented in 65nm CMOS for applications in sensor networks and wireless tagging. This fully self-sufficient system has no pads or external components (e.g. power supply), and the entire radio is a single 3.7mm × 1.2mm chip. To provide multi-access, and to mitigate interference, it uses two separate mm-wave bands for RX/TX and integrates both antennas to provide a measured communication range of 50cm. Compared to mm-sized passive radio solutions in the same category this system provides an order of magnitude range enhancement while improving input sensitivity by >14dB. Wideband pulse transmission enables real-time localization with time-of-flight. The entire system operates with standby harvested power below 1.5μW and aggregate rate >12Mbps.
    No preview · Conference Paper · Jun 2014
  • Hao Nan · Amin Arbabian
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    ABSTRACT: Microwave-induced thermoacoustic (TA) imaging combines the soft-tissue contrast of microwave signals with the resolution of ultrasound (US) imaging without posing any ionizing radiation. Prior work uses short but powerful pulses from a large vacuum source to excite tissue and requires an output power in excess of several kW to achieve sufficient SNR. This poses safety concerns as well as to render the imager large and bulky. In this paper, we propose and demonstrate stepped-frequency continuous-wave (SFCW) and frequency-modulated continuous-wave (FMCW) approaches for microwave-induced thermoacoustic imaging at 2GHz. In the experiment, the FMCW approach achieves a 26dB SNR improvement compared to pulse approach with the same peak output power, averaging window, and receiver gain. To the best of our knowledge this is the first demonstration of full coherency across microwave and acoustic domains with the thermo-elastic response and successful demonstration of frequency-domain microwave TA imaging.
    No preview · Conference Paper · Jun 2014
  • M.S. Aliroteh · G. Scott · A. Arbabian
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    ABSTRACT: Magneto-acoustic (MA) tomography combines near-field RF and ultrasound for the goal of a safe, high-resolution, high-contrast bimodal imaging technique. Coherency between RF excitation and the resulting ultrasound generation through Lorentz force interactions is established. This allows for continuous-wave (CW) imaging techniques to replace conventional pulsed-based approaches, easing system design and improving signal-to-noise ratio (SNR) while reducing the peak-toaverage excitation power ratio, for the same averaging time, sensitivity and gain. This is the first successful demonstration of MA detection using step frequency CW (SFCW) as well as frequency-modulated CW (FMCW) approaches with up to 36 dB SNR improvement.
    No preview · Article · May 2014 · Electronics Letters
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    ABSTRACT: We propose to use acoustic power delivery for sub-mm(3)medical implants, and we have designed acoustic receivers for investigating this technique of wireless power transmission. Compared with radio frequency and inductive transfer, acoustic power transfer gives more favorable impedance and available power for miniaturized and deeply implanted medical devices. Sub-mm(3)dimensions are attractive for many different medical applications; however, there is little literature describing the properties or capabilities of miniaturized acoustic receivers, which is the topic of our investigation. Design of efficient miniaturized implants is challenging because of increased losses due to tissue absorption and coupling to parasitic resonant modes. We will present power transfer and impedance measurements of volumetrically scaled acoustic transducers through several thicknesses of tissue. Our measurements show significant available power with high output voltage, resulting from large transducer impedance, which is useful for overcoming threshold voltages of rectifier circuits. Preliminary measurements show the delivery of 340 μW of average AC power to a 1 mm(2) receiver through 3 cm of tissue with an intensity well below the FDA limit. In addition, we will compare our measurements with piezoelectric theory and discuss trends and limits of available power and impedance as a function of volume and transmit distance.
    No preview · Article · Apr 2014 · The Journal of the Acoustical Society of America
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    ABSTRACT: High-resolution mm-wave array beamformers have applications in medical imaging, gesture recognition, and navigation. A scalable array architecture for 3D imaging is proposed in which single-element phase coherent transceiver (TRX) chips, with programmable TX pulse delay capability, are mounted on a common board to realize the array. This paper presents the design of the enabling TRX chip: a highly integrated 94 GHz phase-coherent pulsed-radar with on-chip antennas. The TRX achieves 10 GHz of frequency tuning range and 300 ps of contiguous pulse position control, enabling its usage in the large-array imager with time-domain TX beamforming. The TRX is capable of transmitting and receiving pulses down to 36 ps, translating to 30 GHz of bandwidth. Interferometric measurements show the TRX can obtain single-target range resolution better than 375 $mu$m (limited by equipment). Based on delay measurements, the time of arrival rms error would be less than 1.3 ps which, if used in a 3D imaging array, leads to less than 0.36 mm of RMS error in voxel size and position.
    No preview · Article · Apr 2013 · IEEE Journal of Solid-State Circuits
  • N. Dolatsha · A. Arbabian
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    ABSTRACT: Design of an all-electrical and easy to package wideband chip-to-chip solution on a multi-mode dielectric waveguide is discussed. Different parameters such as bandwidth-per-pitch, range, as well as crosstalk in aggregated lines are analyzed. Using a Rogers RO3006 material, a bandwidth-per-pitch of 16GHz/mm (and an absolute bandwidth-per-line of 2 × 40 GHz) at the center frequency of 100 GHz is achieved while maintaining a range of 1m with crosstalk below 15 dB. The sensitivity of the line to the curvature is also examined. The signal is coupled from the silicon chip to the degenerate fundamental and polarization-orthogonal Ex11 and Ey11 waveguide modes using planar electric and slot dipole antennas, respectively. The large available bandwidth will be channelized in frequency for optimal overall efficiency and throughput with a CMOS transceiver. The performance sensitivity of the structure to possible fabrication imperfections is examined and discussed. The proposed waveguide offers a solution for Tera bit-per-second (Tbps) fully-electrical wireline links.
    No preview · Article · Jan 2013
  • N. Dolatsha · A. Arbabian
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    ABSTRACT: An all-electrical, low-cost, wideband chip-to-chip link on a multi-mode dielectric waveguide is proposed. The signal is coupled from the silicon chip to the fundamental and polarization-orthogonal degenerate Ex11 and Ey11 waveguide modes using planar electric and slot dipole antennas, respectively. This approach doubles the capacity of a single line without sacrificing robustness or adding implementation cost and complexity. Two independent ultra-wideband 30GHz channels, each from 90 GHz to 120 GHz, are demonstrated. The large available bandwidth will be channelized in frequency for optimal overall efficiency with a CMOS transceiver. Various design aspects of the structure are examined and discussed. The proposed waveguide offers a solution for Terabit-per-second (Tbps) electrical wireline links.
    No preview · Conference Paper · Jan 2013
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    ABSTRACT: An integrated phase-coherent and pixel-scalable pulsed-radar transceiver with on-chip tapered loop antennas generates programmable pulses down to 36ps using an integrated 94GHz carrier, frequency synthesized and locked to an external reference. A DLL controls the TX pulse position with 2.28ps resolution, which allows the chip to function as a unit element in a timed-array. The receiver also features a >;1.5THz GBW DA as the front-end amplifier, quadrature mixers, and a 26GHz quadrature baseband. Phase coherency allows for ~375μm single-target position resolution by interferometry.
    No preview · Conference Paper · Jun 2012
  • Amin Arbabian · Ali M. Niknejad
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    ABSTRACT: A three-stage cascaded distributed amplifier is designed in a 0.13μm SiGe BiCMOS process. By optimizing the amplifier both at the architecture and element level, an extremely large measured gain-bandwidth product in excess of 1.5THz is obtained. The core amplifier consumes 75mA from a 3.3V supply and provides an average gain of 24dB from 15GHz to at least 110GHz (limited by equipment BW). A distributed RF-choke design is employed to provide the bias current to the three cascaded stages. The pass-band gain stays between 23 and 26.5dB.
    No preview · Conference Paper · Jun 2012
  • Maryam Tabesh · Amin Arbabian · Ali M. Niknejad
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    ABSTRACT: Two compact, low-loss, passive reflective type 60GHz phase shifters are presented in a standard 65nm CMOS technology. The designs use lumped-element baluns to implement the hybrid with an insertion loss better than 0.7dB. The first architecture achieves 180 degrees phase shift with an average loss of 6.6dB and area of 0.031mm2. The second phase shifter demonstrates the best reported average loss of 4.5dB with an area of 0.048mm2 while having ~150 degrees of phase shift. Both designs provide more than 10GHz of bandwidth. These are the smallest reported 60GHz phase shifters in silicon.
    No preview · Conference Paper · Sep 2011
  • Amin Arbabian · Ali M Niknejad
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    ABSTRACT: This paper introduces a silicon-based imaging array for remote measurements of complex permittivity of tissue. Using a coherent pulsed measurement approach, this time-frequency resolved technique recovers the three dimensional mapping of electrical properties of the subject in the microwave/millimeter-wave frequency spectrum. Some of the major challenges in the design of the system are described. Initial measurement results from the prototype high-resolution transmitter fabricated in a 0.13 μm SiGe process are described. The transmitter achieves pulse widths suitable for millimeter-level accuracy imaging.
    No preview · Article · Aug 2011 · Conference proceedings: ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Conference
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    ABSTRACT: A reflective, dual-loop, switching antenna utilizing near-field/far-field energy cancellation is integrated in a 90 GHz pulsed transmitter (TX). The TX features high ON/OFF ratio, good antenna efficiency and PRF up to 3.45 GHz. It achieves TX power of 10 dBm with 18 dB of power tuning. The pulse width is tunable between 46 ps to 310 ps and initial bistatic measurements distinguish 4 reflectors across a 6 cm region signifying progress towards the development of a diagnostic medical imager in silicon.
    No preview · Article · Jun 2011