Amin Arbabian

A 90 nm CMOS Low-Power 60 GHz Transceiver With Integrated Baseband Circuitry

This paper presents a low power 60 GHz transceiver that includes RF, LO, PLL and BB signal paths integrated into a single chip. The transceiver has been fabricated in a standard 90 nm CMOS process and includes specially designed ESD protection on all mm-wave pads. With a 1.2 V supply the chip consumes 170 mW while transmitting 10 dBm and 138 mW while receiving. Data transmission up to 5 Gb/s on each of I and Q channels has been measured, as has data reception over a 1 m wireless link at 4 Gb/s QPSK with less than 10-11 BER.

A 94 GHz mm-Wave-to-Baseband Pulsed-Radar Transceiver with Applications in Imaging and Gesture Recognition

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 μm (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.

A mm-Sized Implantable Medical Device (IMD) With Ultrasonic Power Transfer and a Hybrid Bi-Directional Data Link

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 μW to a few mWs) required for most implant applications. The current implant prototype measures 4 mm ×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 μW for an incident acoustic intensity that is ~ 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.

Design of a CMOS Tapered Cascaded Multistage Distributed Amplifier

This paper presents the design and measurement of a distributed amplifier (DA) in a standard 90-nm CMOS process. To improve the gain and bandwidth (BW) of the DA, the use of an elevated coplanar waveguide line and also impedance tapering in the synthesized sections are proposed. The effects of elevation and shielding filaments on the impedance, loss, and effective dielectric constant of the transmission line are investigated and accompanied by measurements. A methodology for CMOS DA design is described that can take advantage of the multiple degrees of freedom in terms of device size, topology, and aspect ratio available in these processes. The fabricated tapered cascaded multistage DA achieves a 3-dB BW of 73.5 GHz with a passband gain of 14 dB. This results in a gain-BW product of 370 GHz. The realized 0-dB BW is 83.5 GHz and the input and output matchings stay better than -9 dB up to 77 and 94 GHz, respectively. The chip consumes an area of 1.5 mm times 1.15 mm, while drawing 70 mA from a 1.2-V supply.

A 90 GHz Hybrid Switching Pulsed-Transmitter for Medical Imaging

This paper reports a fully integrated 90 GHz-carrier pulsed transmitter in 0.13 μm SiGe BiCMOS process for imaging applications. To obtain ultra-short programmable pulses, the transmitter employs a number of novel techniques including hybrid switching and Antentronics. The transmit path includes a quadrature VCO, PA driver, PA and the on-chip folded slot antenna. High speed ECL circuits generate and provide the short pulses in several operating modes. The transmitter achieves a record pulsewidth of 26 ps in the hybrid mode and 33 ps in the independent mode. This translates to >30 GHz of RF BW in the transmitter.

A Broadband Distributed Amplifier with Internal Feedback Providing 660GHz GBW in 90nm CMOS

In the presented DA (distributed amplifier) architecture, a feedback mechanism that aims at improving the gain with a minimum reduction in BW is proposed. It is seen that in the band where the distributed effect of the DA is in action, the ratio of the forward to reverse gain is substantial (and depends on the number of stages used). The input and output blocks are connected to this core stage to provide matching and stability This method is different from other techniques that improve gain (e.g., cascade of DAs or matrix amplifier) in that it uses a new internal feedback to fed signals go through one DA twice. The input, core and output DA blocks consist of 4/3/3 gain elements respectively except that the core DA uses series input capacitances at the gates for BW enhancement and biasing purposes. Terminations Zx and Zy are chosen to minimize undesired reflections. The input and output biases are fed through appropriate bias tees. The lower cutoff of the DA is set at 12 GHz for our application in a wideband mm-wave imaging module. This frequency could be extended to frequencies close to 1 GHz if appropriate AC-coupling capacitors are used.

A Power-Harvesting Pad-Less Millimeter-Sized Radio

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.

Stepped-frequency continuous-wave microwave-induced thermoacoustic imaging

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.

60GHz low-loss compact phase shifters using a transformer-based hybrid in 65nm CMOS

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.

A tapered cascaded multi-stage distributed amplifier with 370GHz GBW in 90nm CMOS

A tapered cascaded multi-stage distributed amplifier (T-CMSDA) has been designed and fabricated in a 90 nm digital CMOS process. The amplifier achieves a 3-dB bandwidth of 73.5 GHz with a pass-band gain of 14 dB. This results in a gain-bandwidth (GBW) product of 370 GHz. The realized zero-dB BW is 83.5 GHz and the input and output matchings stay better than -9 dB up to 77 and 94 GHz, respectively. The chip consumes an area of 1.5 mm by 1.15 mm while drawing 70 mA from a 1.2 V supply.