Alireza Zandieh

Silicon-on-Glass Dielectric Waveguide—Part I: For Millimeter-Wave Integrated Circuits

A low-cost Silicon-on-Glass (SOG) integrated circuit technology is proposed for millimeter-wave (mmW) applications, for the first time. In the proposed technology, all mmW passive components are made of high-resistivity Silicon (Si) on a glass substrate. The proposed technique leads to a high-precision and low-cost fabrication process, which eliminates the need for costly assembly of the complex structures. This is achieved by photolithography and dry etching of the entire integrated passive circuit through the Si layer of the SOG wafer. Silicon-on-Glass dielectric waveguide, as the basic component of the SOG integrated circuit, is theoretically and experimentally investigated. A test setup is designed to measure propagation characteristics of the proposed SOG waveguide. Measured dispersion diagrams of the SOG dielectric waveguide show average attenuation constants of 0.63 dB/cm, 0.28 dB/cm, and 0.53 dB/cm over 55-65 GHz, 90-110 GHz, and 140-170 GHz, respectively.

CPW-fed chip-scale dielectric resonator antenna for millimeter wave applications

Two different designs were proposed for Dielectric Resonator Antenna with CPW-Fed slot. Significant miniaturized with high efficiency antenna was presented using DRA with high relative permittivity. However, to achieve wider bandwidth, another design employing DRA with low relative permittivity was considered. To compensate low gain of latter case, higher order mode was excited inside the DRA.

A low-loss CPW to dielectric waveguide transition for millimeter-wave hybrid integration

A transition from a coplanar waveguide (CPW) to a dielectric waveguide is investigated for the integration of active devices into dielectric waveguide structures. The transition consists of three parts: CPW to a slot line, the slot line to a dielectric waveguide, and a linear tapering part for matching the first and the last parts, respectively. The maximum of insertion loss is -1.7dB, and the return loss is less than -15dB over 7% bandwidth at 60GHz.

Compact and reconfigurable fiber-based terahertz spectrometer at 1550 nm

In this paper, we present a new compact and versatile spectrometer system operating at 1.55 μm for research and industrial application. The system is capable of testing solid, powder, thin film, gas, and liquid samples for material sensing and characterization applications. A high efficient system with bandwidth up to 1.2 THz is realized by using a fiber coupled terahertz chip packaging technology. The key components are the fiber-coupled THz transmitter and receiver modules, where the laser beam is directly coupled to the THz chip using optical fibers to provide stable and movable transmitter and receiver heads. The antennas are excited by 100 fs optical pulses at 1550 nm telecom wavelength and average power of 10mW. As femtosecond pulses are required on the antenna, the linear dispersion and nonlinear effect resulting from the propagation of the high power optical pulse along the fiber are taken into account and compensated using dispersion compensation fiber. A fast scan optical delay module is employed to realize real-time THz signal and spectrum measurement. The optical delay module also has a long delay scan unit to allow the user to adjust the distance between the transmitter and receiver heads by up to 1m to use the system for characterization of materials in different industrial applications.

Millimeter-wave high gain parasitic tapered antenna made of high-resistivity silicon image-guide

A novel high gain dielectric tapered antenna, operating at the W-band, is presented. The image-guide antenna is made of high-resistivity Silicon. Two short parasitic tapered elements are used to increase the antenna gain and to reduce the side-lobe levels. A Laser cutting technique is tuned for the fabrication of the prototype antenna. The results show a return loss better than 22 dB at 90 GHz. The simulated gain is around 13.1 dBi and the radiation efficiency is 97%.

High resistivity silicon DRA array for millimeter-wave high gain applications

The paper presents the design, and measurement results of a new millimeter-wave Dielectric Resonator Antenna (DRA) array implemented in high resistivity Silicon Image Guide (SIG) technology. The proposed SIG antenna offers a low-cost, and high gain DRA array concept for millimeter-wave applications. The design includes a low loss SIG power splitter which has been used to feed the 4-by10 antenna array. The antenna with the feed has a measured return loss better than −10 dB within the frequency range from 90 GHz to 110 GHz. The measured gain is 19 dB at 97 GHz. The measurements data are in good agreement with the simulation results. A single mask dry etching process has been used to realize the proposed antenna. A group of narrow non-radiative supporting beams are designed to enhance the structure mechanical stability.

High efficiency sawtooth side-grating millimeter-wave antenna

This paper presents a new dielectric grating antenna based on high resistivity silicon image guide technology. The radiation is due to triangular shaped (sawtooth) dielectric gratings on the both sides of the image guide. The proposed antenna has been fabricated with a low cost single mask deep reactive-ion-etching process. The proposed optimized antenna is well-matched over the W band with radiation efficiency of 95%. Measurements and simulations of both return loss and radiation pattern are in good agreement.

THZ devices evaluation in a time domain spectroscopy system at 1.55 μm pulse excitation

Following the development of efficient THz devices operating at 1550 nm based on low temperature (LT) grown semiconductor compounds, the effect of the substrate of such devices in the generated THz radiation is investigated, a new compact, portable and reconfigurable fiber based THz spectrometer is built and a pair of THz devices are evaluated in the spectrometer. The key findings are firstly the transparency of the InP substrate to THz radiation, which implies that the generated THz signal from these devices is not affected by the substrate, and secondly the development of a THz spectrometer at 1550 nm laser excitation, which can be used for high quality measurements for various material sensing and characterization applications.

Novel high efficiency side-grating millimeter-wave antenna

A new dielectric grating antenna is proposed in this paper. The proposed all-silicon antenna consists of a rectangular dielectric waveguide with rectangular gratings on its both sides. This type of grating can be fabricated with low cost single print deep reactive-ion-etching process. The radiation mechanism in the proposed structure, is based on the power leakage of the order -1 space harmonic (Floquets mode). The proposed optimized 94GHz antenna is well-matched over a more than 10% bandwidth with a frequency scanning ability up to 25° (1dB variations in the gain).