Nemat Dolatsha

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.

Millimeter-Wave Chip-to-Chip Transmission Using an Insulated Image Guide Excited by an On-Chip Dipole Antenna at 90 GHz

A millimeter-wave chip-to-chip transmission link operating at 90 GHz is presented. It uses an insulated image guide and on-chip dipole antennas positioned in the entrance of the waveguide for excitation and reception. The on-chip dipole antenna couples to the higher-order Ex11 mode of a synthesized insulated image waveguide. This field coupling avoids the need for conductive connections such as wire-bonds or flip-chip technology. The measured insertion loss of such a field-coupled dipole-to-image guide transition is 0.46 dB at 90 GHz.

System-Level Analysis of Far-Field Radio Frequency Power Delivery for mm-Sized Sensor Nodes

Millimeter-sized and low-cost sensor nodes can enable future applications of the Internet of Things (IoT), for which the number of sensors is projected to grow to a trillion within the next decades. RF far-field power transfer is a potential technique for wirelessly powering these sensors since it offers flexible configuration of sensor networks, beamforming capability and a large power transfer range compared to near-field approaches. However, system design for RF power transfer needs to be completely rethought to enable this new paradigm of a trillion IoT sensors. This paper, therefore, presents a comprehensive, system-level analysis strategy and a modular framework for investigating the fundamental efficiency components in an RF power transfer chain. Through this detailed analysis, it is demonstrated that the optimal frequency is primarily determined by the antenna size and the quality factors (Q) of components in the matching network. Millimeter-wave frequencies are shown to be optimal for powering mm-sized sensors for practical matching component Q values. An intuitive explanation of our results is also provided, along with insights for the design and practical implementation of RF power transfer systems for the IoT space.

Dielectric waveguide with planar multi-mode excitation for high data-rate chip-to-chip interconnects

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.

A 135GHz SiGe transmitter with a dielectric rod antenna-in-package for high EIRP/channel arrays

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.

Standoff tracking of medical interventional devices using non-contact microwave thermoacoustic detection

Tracking of medical interventional devices is performed using non-contact microwave-induced thermoacoustic detection. The interventional device is modeled with an exposed tip coaxial probe in an agar phantom and it uses the inherent microwave excitation to generate modulated thermoacoustic signals. The resulting ultrasound signal is detected by custom designed capacitive micromachined ultrasonic transducers (CMUTs) at a standoff and without any contact with the target. The dependency of the specific absorption rate (SAR) profile on the excitation frequency and probe tip length is examined in order to determine optimal operating conditions for resolution and signal level. An excitation frequency of 2.35 GHz is chosen and is amplitude-modulated with a 72 kHz pulse train to match the center frequency of the CMUTs. A two transducer system is employed to achieve cm-scale resolution via 2-dimensional location tracking using a modified trilateration technique.

Millimeter-Wave Antenna Array Fed by an Insulated Image Guide Operating in Higher-Order

This communication presents a low-loss hybrid technology for integration of planar circuits with high-efficiency off-chip antennas. A linear antenna array fed by a low-loss synthesized version of insulated image guide operating in E11x mode (where the electric field is primarily parallel to the ground-plane) is designed and measured. A planar on-chip electric dipole couples fields efficiently from planar circuits to the antenna array feed line. Measured coupling insertion loss is about 0.5 dB at 90 GHz. A broadside gain of 14.9 dBi at 90 GHz is measured for an array with 10 radiating elements.

E^{11}_x

Available data on the dielectric properties of biological tissue across a frequency range adds an extra degree of freedom of contrast besides the baseline structural information obtained by conventional imaging techniques. In this paper, we propose a new methodology to non-invasively extract the normalized effective conductivity of samples over a large frequency range using microwave-induced thermoacoustic (TA) signals. Additionally, a calibration approach has been adopted to remove the frequency dependency of the experimental setup errors as well as the RF power variation. The linear relationship between the TA signal amplitude on the absorbed microwave power is used to extract the properties of samples. Saline phantoms with various concentration are used to mimic different tissue materials in the proof-of-concept experiment. The extracted normalized effective conductivity by the proposed method matches the theoretical calculations as well as the direct contact measurements by a dielectric probe.

Mode

We investigate the fundamental physical constraints and tradeoffs in common millimeter-wave dielectric waveguides proposed for high speed links. We consider waveguides with different geometries, dimensions and operating frequencies, and show that the capacity of optimized longer links is limited by the dispersion and not necessarily the loss. In our analysis, the required capacity and distance determine the choice of waveguide and the operating frequency, which would then determine the energy efficiency of the link. Our generic theoretical analyses are in agreement with the measurements presented in the recent literature.

Extracting dielectric spectroscopic properties from microwave-induced thermoacoustic signals

Low-cost, energy efficient, high-capacity, scalable, and easy-to-deploy point-to-point wireless links at mm-waves find a variety of applications including data intensive systems (e.g., data centers), interactive kiosks, and many emerging applications requiring data pipelines. Operating above 100GHz enables compact low-footprint system solutions that can multiplex Tb/s aggregate rates for dense deployments; therefore competing with wired solution in many aspects including rate and efficiency, but much more flexible for deployment. The focus is on small-footprint fully integrated solutions, which overcome traditional packaging challenges imposed at >100GHz with commercial and low-cost solutions.