Silicon-Based Structures for mm/THz Applications

Research Projects:

The primary focus of this research is to develop a novel silicon waveguide-based technology for implementing various structures and devices in the mmWave and THz range of frequencies.  The structures introduced in this study are designed based on High Resistivity Silicon (HRS). Two technologies are developed and investigated at the Centre for Intelligent Antenna and Radio Systems (CIARS): Silicon-On-Glass (SOG) and Silicon Image Guide (SIG) technologies. The proposed technologies provide a low-cost, highly efficient, and integratable platform for realization of a variety of mmWave/THz systems suitable for various applications such as sensing, communication, and imaging.
A vast range of passive structures such as bends, dividers, antennas, and couplers are designed, fabricated and successfully tested with desired performance at the mmWave range of frequencies.
The proposed HRS platforms are used for implementing various WGM resonance configurations. The introduced Whispering Gallery Mode (WGM) structures are employed for two major applications: DNA sensing and resonance tuning. The results for DNA testing are quite impressive in being able to distinguish between different kinds of DNA.

Silicon-On-Glass (SOG) Technology:

Main aspects of SOG technology:

• Low-cost / Low-loss.
• Integratable.
• Best Competitor for MWG.
• Fabricated and tested up to 500 GHz.

Fabricated corrugated SOG structures: a) Straight waveguide., b)WGM disc resonator, c) WGM disc resonator.

Fabricated straight waveguide on corrugated SOG technology

The schematic of the straight waveguide on corrugated SOG technology

Silicon Image Guide (SIG) Technology:

Main aspects of SIG technology:

• Simple and Low-cost.
• Laser Machined fabrication.
• mask-free, chemical-free, fast, and low-cost process.
• Ease to  test.



The straight SIG structures fabricated by the laser machining process

The measurement setup

The measurement and simulation results for two different lengths of the fabricated straight waveguide (SW) SIG structures.

SIG Antenna:

Main aspects of SIG antenna:

• High efficient antennas >95%.
• Frequency: W-band and D-band.
• low cost.
• High gain and low side lobe level.

Strip grating SIG Antenna.

High gain parasitic antenna


The straight SIG structures fabricated by the laser machining process


The straight SIG structures fabricated by the laser machining process

SIG Passive Components:


SIG bend

SIG Coupler


SIG Divder


SIG Coupler


The measured S-parameters for the fabricated bend

Tunable SOG WGM Resonator:


Schematic diagram of the tunable SOG WGM

The fabricated tunable SOG WGM

The measurement results.


The Measurement setup

Finger Shaped Phase Shifter on SOG Technology:

Main aspects of phase shifter:

• Low cost.
• Easy to integrate.
• Wide band over G-band.
• Max. Phase Shift: 33.5 degree/mm.

The laser machined movable part of the finger-shaped phase shifter.

Zoomed picture of the movable part of the finger-shaped phase shifter


Schematic of the finger shaped phase shifter


The measured phase shift of the finger-shaped phase shifter (the length of finger structure is 3 mm and the movement part is 200 mm).

Integrated Antennas and Active Beamformers Technology for mm-wave Phased Array Systems:

Within this project, the following topics are investigated:

• Novel switched beam high resistivity silicon Antenna for Automotive Radar System.
• PCB Antenna Array for Automotive Digital Beam Forming Radar.
• GPU-based Ray Tracing tool for Automotive Radar and indoor channel modelling.
• Phase Shifter for Car to Satellite ka-band Phased Array Antenna System.
• Novel mmWave/sub-THz on-chip antenna.
• CPW based mmWave filter.
• mmWave/sub-THz low loss wide band transitions (Rectangular Waveguide to Microstrip line, Rectangular Waveguide to Dielectric Waveguide, CPW line to Dielectric Waveguide and Flipchip to CPW line).

– Dielectric Waveguide for High Performance millimeter-wave/THz Integrated Systems:

The Project concentrates on a low-cost and low-loss Silicon-on-Glass (SOG) integrated technology for millimeter-wave/THz applications. In the proposed technology, all millimeter-wave/THz 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 complex structures. This is achieved by dry etching of the entire integrated passive circuit through the Si layer of a SOG wafer. SOG dielectric waveguide, as the basic component of the SOG integrated circuit, is theoretically and experimentally investigated.