Ilja Ocket

Study of active millimeter-wave image speckle reduction by Hadamard phase pattern illumination

Active millimeter-wave images typically exhibit characteristic speckle noise, due to the coherence of artificial millimeter-wave sources. We study the Hadamard speckle contrast reduction (SCR) technique, which has been successfully used in laser projection systems, in the context of millimeter-wave imaging. We show the impact of Hadamard pattern order and size and of image and pattern resolution on speckle reduction efficiency. Practical limitations of Hadamard pattern implementations and their effect on speckle reduction efficiency are also discussed.

A system-level simulator for indoor mmW SAR imaging and its applications

Recently, the research interest in indoor active millimeter wave (mmW) imaging by applying the synthetic aperture radar (SAR) technique is increasing. However, there is a lack of proper computer-aided design (CAD) tools at the system level, and almost all the R&D activities rely on experiments solely. The high cost of such a system stops many researchers from investigating such a fascinating research topic. Moreover, the experiment-oriented studies may blind the researchers to some details during the imaging process, since in most cases they are only interested in the readout from the receivers and do not know how the waves perform in reality. To bridge such a gap, we propose a modeling approach at mmW frequencies, which is able to simulate the physical process during SAR imaging. We are not going to discuss about advanced image reconstruction algorithms, since they have already been investigated intensively for decades. To distinguish from previous work, for the first time, we model the data acquisition process in a SAR imaging system successfully at mmW frequencies. We show how to perform some system-level studies based on such a simulator via a common PC, including the influence of reflectivity contrast between object and background, sampling step, and antennas directivity on image quality. The simulator can serve system design purposes and it can be easily extended to THz frequencies.

60 GHz ultra low phase noise sige common base oscillator using a wirebond coupled mcm integrated micromachined cavity resonator

This paper reports on a 60 GHz common base fundamental oscillator with ultra low phase noise realized in QUBIC4Xpsilas HBT technology. It uses a silicon micromachined cavity resonator which is mounted on a common MCM PASSI3I carrier and coupled to the MMIC. A novel feed approach is presented which uses a wirebond to couple the interconnecting CPW line to the KOH-etched silicon cavity of which the advantages are ease of manufacture and reduced substrate effects compared to other coupling approaches. Oscillator measurement results for the stand-alone MMIC are presented and compared to 2.5D/3D simulations. The important effect of wirebond shape variability is quantified in terms of oscillation frequency, output power and phase noise.

Microwave heater at 20 GHz for nanoliter scale digital microfluidics

This paper proposes an optimized microwave heater at 20 GHz for nanoliter scale liquid samples in digital microfluidics. The developed measurement setup allows translating of the reflection coefficient of the heater to the temperature change of the water droplet via the temperature dependency of the liquid permittivity, thus avoiding a contact-based temperature measurement. Measurements have been carried out on pure water samples of 500 nL at power levels of 20 and 23 dBm at the probe tips. The measured data agrees very well with multiphysics simulation data. Heating performance has been characterized and high temperature gradients of 30 deg. C per second have been measured.

Sensitivity Analysis of Broadband On-Wafer Dielectric Spectroscopy of Yeast Cell Suspensions up to 110 GHz

This letter presents broadband on-wafer dielectric spectroscopy of bakers yeast cell suspensions up to 110 GHz. A detailed analysis of the sensitivities to measurement repeatability and uncertainties in the multi-step de-embedding procedure is performed. The Cole-Cole dispersion parameters of the cell suspensions are obtained from measured complex permittivity data between 0.5 and 110 GHz. Our analysis shows that the measured complex permittivity per frequency is most sensitive to length uncertainties of the test fixture, while the relaxation time in the Cole-Cole model is most sensitive to measurement repeatability.

Millimeter wave on-wafer measurement of yeast cell suspension using a CPW test fixture in LCP technology

This paper deals with the measurement of cell suspensions at millimeter wave frequencies between 30 GHz and 110 GHz using a CPW test fixture and an on-wafer network analyzer set-up. The measurement results show that yeast cell suspension with concentration as low as 4 million cells/ml or 4 cells/nl can be distinguished from water by their dielectric constants at millimeter wave frequencies. High contrast in the imaginary part of the permittivity is found for cell concentrations from 4 million cells/ml to 4 billion cells/ml.

Fine pitch 3D-TSV based high frequency components for RF MEMS applications

The development of interconnections suitable for radio-frequency (RF) and millimeter-wave (mm-wave) applications is of foremost importance for the feasibility of high-quality substrate-integrated devices. For this purpose, we introduce and validate the technology to implement fine-pitch high-aspect ratio tungsten-filled through-silicon vias (W-TSVs) adapted for high-frequency applications. The presented technology is optimized for integration with RF MEMS, for which we propose a compatible fabrication process flow. We designed and characterized RF test structures to assess the quality of the W-TSVs and their suitability for radio-frequency integrated circuits (RFIC) applications, showing low insertion loss for TSV in coplanar waveguides (CPW) and high-performance wideband mm-wave antennas.

Millimeter wave micromachined cavity resonators on MCM-D: Oscillator-resonator co-design and packaging considerations

This paper reports on the integration of millimeter wave micromachined cavity resonators on MCM-D and their optimization for use in ultra low phase noise oscillator modules at 60 GHz and 77 GHz. We will discuss some important oscillator/resonator co-design and packaging considerations in order to optimally take advantage of the high inherent quality factor of these cavity resonators. In addition we will present modeling and measurement results for CPW slot coupled cavities around 60 GHz and 74.3 GHz mounted onto an MCM-D carrier realized in IMECs 3D-IPD technology. The measured cavity resonators showed resonant frequencies of 58.89 GHz and 75.26 GHz with unloaded quality factors of 755 and 300, respectively. These agree extremely well to the simulated values of 58.92 GHz and 75.27 GHz for the resonant frequency and 879 and 323 for the quality factor. These values include the effects of a long CPW line and of coupling losses which are largely due to parasitic substrate modes.

60 GHz Si micromachined cavity resonator on MCM-D

This paper describes a 60 GHz high-Q cavity resonator etched in silicon. This cavity is flip-chip bonded to an MCM-D HRSi substrate containing the planar feed structure. The quality factor of the resonator without feed as predicted by HFSS is 1506 at 60 GHz. Substrate mode excitation by the feed is suppressed by using a semi-shielded cavity underneath the coupling slot. Design data together with a fitted lumped element model are presented for the resonator with feed and show a simulated Q of 1220.

An Improved Line-Reflect-Reflect-Match Calibration With an Enhanced Load Model

An improved line-reflect-reflect-match calibration with an enhanced load model is proposed. Different from load models used by existing LRRM algorithms, the load model used in the proposed algorithm takes into account both the parasitic capacitance and inductance. Using the same calibration standards as the classical LRRM and the enhanced LRRM, the proposed algorithm can accurately determine the load parasitics from raw measurements. Measurement results from 0.5 GHz to 110 GHz on a commercial impedance standards substrate show that the proposed LRRM outperforms the classical LRRM and the enhanced LRRM, and gives multiline TRL quality on-wafer calibrations.