Nemat Dolatsha - Academia.edu (original) (raw)

Papers by Nemat Dolatsha

Soil and Tillage Research, 2012

$Research paper thumbnail of Millimeter-Wave Antenna Array Fed by an Insulated Image Guide Operating in Higher-Order <formula formulatype="inline"><tex Notation="TeX">$E^{11}_x$</tex> </formula> Mode$

IEEE Transactions on Antennas and Propagation, 2013

This communication presents a low-loss hybrid technology for integration of planar circuits with ... more 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 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.

IEEE Microwave and Wireless Components Letters, 2012

IEEE Transactions on Antennas and Propagation, 2016

Ball Grid Array-module (BGA-module) incorporating a low-cost shaped dielectric lens is proposed f... more Ball Grid Array-module (BGA-module) incorporating a low-cost shaped dielectric lens is proposed for wireless communications in the 60GHz WiGig band between a smart eyewear where it is integrated and a facing laptop or TV. The module, which is co-designed with a 60GHz transceiver, consists of two separate identical antennas for transmitting (Tx) and receiving (Rx). The in-plane separation of these elements is 6.9mm both being offset from the lens focus. This poses a challenge to the lens design to ensure coincident beam pointing directions for Rx and Tx. The shaped lens is further required to narrow the angular coverage in the elevation plane and broaden it in the horizontal plane. A 3-D-printed eyewear frame with an integrated lens and a recess for proper BGA-module integration is fabricated in ABS-plastic material. Measurements show a reflection coefficient below-12dB in the 57-66GHz band. A maximum gain of 11dBi is obtained at 60GHz, with 24 o and 96 o beamwidth at 5dBi gain respectively in the vertical and horizontal planes. The radiation exposure is evaluated for a homogeneous SAM head phantom and a heterogeneous visible human head. The simulated power density values for both models are found to be lower than the existing standards. Index Terms-WiGig, eyewear, 60GHz, lens antennas, antenna-in-package, plastic packaging I. INTRODUCTION ith the never-ending improvement of the capabilities of wireless communication devices, the most critical necessity has been to supply the user with higher and higher data rates. This has led to both the improvement of the Manuscript

2012 IEEE/MTT-S International Microwave Symposium Digest, 2012

An insulated image guide operating in Ex11 mode (where the electric field is primarily parallel t... more An insulated image guide operating in Ex11 mode (where the electric field is primarily parallel to the ground-plane) is investigated experimentally and by simulations in the frequency range of 80 GHz to 100 GHz. The proposed waveguide is characterized by a thick low-permittivity gap layer sandwiched between the ground-plane and the main high permittivity dielectric slab. This waveguide features low propagation loss and low coupling to unwanted modes at discontinuities. A resonator method is applied for accurate measurements. A waveguide based on alumina ceramic as a dielectric (tanδ = 0.002) and brass as ground metal, has an attenuation constant of 0.07 dB/mm at 90 GHz. A 60° bend adds 0.33 dB loss at 90 GHz.

Proceedings of the IEEE 2014 Custom Integrated Circuits Conference, 2014

In this paper, a 135 GHz antenna-in-package (AiP) transmitter with high equivalent isotropic radi... more 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.

2013 IEEE International Conference on Ultra-Wideband (ICUWB), 2013

An all-electrical, low-cost, wideband chip-to-chip link on a multi-mode dielectric waveguide is p... more 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.

IEEE Journal of Solid-State Circuits, 2015

A wireless-powered pad-less single-chip radio is implemented in 65 nm CMOS for applications in In... more 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.

Microwave and Optical Technology Letters, 2012

The use of E 11 x mode in an insulated image guide is proposed. This mode has much lower conducto... more The use of E 11 x mode in an insulated image guide is proposed. This mode has much lower conductor loss than the fundamental, E 11 y mode. The electric field of the mode is primarily parallel to the metal ground-plane; therefore, the mode can be efficiently excited with a compact dipole structure oriented parallel to the ground-plane. When the insulating layer is of low permittivity and relatively thick, the E 11 x mode exhibits the highest effective permittivity (largest propagation constant) of all modes. This reduces unwanted mode coupling at discontinuities. Two example structures, a straight line and a double-bended line are measured at frequencies around 8 GHz. The excitation of the waveguide causes insertion loss of less than 0.4 dB, and the radiation loss of the bends and the waveguide itself appears to be negligible.

Journal of Electromagnetic Waves and Applications, 2008

ABSTRACT In this paper, a via-free compact CPW-based composite right/left-handed transmission lin... more ABSTRACT In this paper, a via-free compact CPW-based composite right/left-handed transmission line (CRLH TL) is presented. The structure is realized by metal-insulator-metal (MIM) series capacitors and shunt coplanar waveguide (CPW) stub inductors. A calibration approach to accurately extract the propagation characteristics of CRLH TLs is also proposed. To demonstrate the extraction technique, three unbalanced CRLH TLs of different lengths are designed and fabricated. The LH-passband with anti-parallel phase and group velocities and the LH/RH-stopband with zero phase constant are successfully determined. For the proposed CRLH TL a LH-passband extending from 0.5 to 2.5 GHz is measured. In comparison with the conventional methods based only on the overall S-parameters of the CRLH TL, the proposed technique offers an accurate extraction of single-mode propagation characteristics. Simulation results are in good agreement with the measurement.

Microwave and Optical Technology Letters, 2009

is 1.25 dB with a return loss better than 28 dB. Two transmission zeros are observed with attenua... more is 1.25 dB with a return loss better than 28 dB. Two transmission zeros are observed with attenuations over 40 dB at approximately 1.43 and 1.93 GHz, respectively. Meanwhile, the measured 3-dB relative bandwidth is about 9.35%. Figure 3(b) describes the measured in-band group delay. The wideband responses, shown in Figure 3(c), illustrate that the first spurious pass-band is located at 3.18 GHz, i.e. about 2f 0. When comparing the measurements with predicated results, one can see that a good agreement between them can be observed. 4. CONCLUSION In this article, a compact dual-mode patch resonator for band-pass filter applications has been studied. A demonstrator filter using a dual-cross slot has been designed, fabricated and tested. Measured data indicate the filter has a minimum pass-band insertion loss 1.25 dB as well as a pair of transmission zeros close to the pass band. The filter has a size reduction to 26.7% as compared to the conventional patch resonator. The design concept is validated, theoretically and experimentally, with good consistency.

2017 IEEE International Solid-State Circuits Conference (ISSCC), 2017

Low-cost, energy efficient, high-capacity, scalable, and easy-to-deploy point-to-point wireless l... more 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.

Design of an all-electrical and easy to package wideband chip-to-chip solution on a multi-mode di... more 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 16 GHz/mm (and an absolute bandwidth-per-line of 2 × 40GHz) at the center frequency of 100GHz is achieved while maintaining a range of 1 m 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 E x and E 11 y 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 novel low-loss planar dielectric waveguide is proposed. It is based on a high-permittivity diel... more A novel low-loss planar dielectric waveguide is proposed. It is based on a high-permittivity dielectric slab parallel to a metal ground. The guiding channel is limited at the sides by a number of air holes which are lowering the effective permittivity. A mode with the electric field primarily parallel to the ground plane is used, similar to the E11x mode of an insulated image guide. A rather thick gap layer between the ground and the high-permittivity slab makes this mode to show the highest effective permittivity. The paper discusses the mode dispersion behaviour and presents measured characteristics of a power divider circuit operating at a frequency of about 8 GHz. Low leakage of about 14% is observed at the discontinuities forming the power divider. Using a compact dipole antenna structure, excitation efficiency of more than 90% is obtained.

Based on a synthesized version of insulated image guide operating in Ex11 mode (where the electri... more Based on a synthesized version of insulated image guide operating in Ex11 mode (where the electric field is primarily parallel to the ground-plane), a low-loss 1:3 power divider is designed and measured. This waveguide is shown to have low transmission loss as well as low radiation loss at bends and dividing junctions. Net insertion loss of about 2.3 dB (or about 10 dB including the loss of the 1:3 division, 4.8 dB, and the loss of planar excitation circuits comprising CPW probe pads and micro-strip baluns) together with excellent phase balance of less than ±9° was measured between 85 GHz and 95 GHz. In addition, a matched load to the image guide mode is presented, based on a field-coupled planar dipole circuit.

Electronics Letters, 2015

A millimetre-wave interconnect on a very low-cost plastic waveguide is proposed for applications ... more 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 E x 11 and E y 11 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.

IEEE Transactions on Terahertz Science and Technology

IEEE Solid-State Circuits Letters

Conference proceedings : ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Annual Conference, 2016

Available data on the dielectric properties of biological tissue across a frequency range adds an... more 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 di...