A varactor-tunable second-order bandpass frequency-selective surface (FSS) for microwave frequenc... more A varactor-tunable second-order bandpass frequency-selective surface (FSS) for microwave frequencies is presented in this article. The FSS is composed of three stacked metallic layers. The wire grid in each layer in combination with metallic vias provides the bias for the varactors. This configuration eliminates the need for a dedicated bias network for the varactors, and thus avoids undesirable responses associated with the added bias grid. An equivalent circuit model together with an analytical design method is provided to simplify the design procedure of the FSS. The performance of the proposed structure is experimentally validated in a parallel-plate waveguide setup. Measurements show that by changing the varactor capacitance from 0.12 to 0.38 pF, the center frequency of the filter is tuned from 5.2 to 3.7 GHz with a consistent fractional bandwidth of 9% and with an insertion loss between 3 and 6 dB.
—In this paper, a compact microfluidic biosensor is designed based on a complementary electric-LC... more —In this paper, a compact microfluidic biosensor is designed based on a complementary electric-LC resonator coupled with a microstrip line. It is shown that by flowing water-glucose solutions with different concentrations to the sensing area, the resonance property of the resonator is modified. This measurable change in the electromagnetic property is then used to quantify the glucose concentration. A prototype of the designed sensor is fabricated and tested to verify the biosensing concept.
—This article presents a design of tunable frequency-selective surface (FSS) with miniaturized el... more —This article presents a design of tunable frequency-selective surface (FSS) with miniaturized elements. The frequency response of this FSS can be tuned by loading varactor diodes in the unit cell. The varactors are biased with a bias network composed of via holes and wire grids. An equivalent circuit model is utilized in the design process. A second-order tunable FSS prototype is designed and simulated for verification of the tunability concept. Full-wave simulations show a 40% tuning range from 5.1 GHz to 3.4 GHz with an insertion loss between 0.7–5.2 dB within the passband.
—A varactor-tunable second-order bandpass frequency-selective surface (FSS) for microwave frequen... more —A varactor-tunable second-order bandpass frequency-selective surface (FSS) for microwave frequencies is presented in this article. The FSS is composed of three stacked metallic layers. The wire grid in each layer in combination with metallic vias provides the bias for the varactors. This configuration eliminates the need for a dedicated bias network for the varactors, and thus avoids undesirable responses associated with the added bias grid. An equivalent circuit model together with an analytical design method is provided to simplify the design procedure of the FSS. The performance of the proposed structure is experimentally validated in a parallel-plate waveguide setup. Measurements show that by changing the varactor capacitance from 0.12 to 0.38 pF, the center frequency of the filter is tuned from 5.2 to 3.7 GHz with a consistent fractional bandwidth of 9% and with an insertion loss between 3 and 6 dB.
Physical unclonable functions (PUFs) are increasingly used for authentication and identification ... more Physical unclonable functions (PUFs) are increasingly used for authentication and identification applications as well as the cryptographic key generation. An important feature of a PUF is the reliance on minute random variations in the fabricated hardware to derive a trusted random key. Currently, most PUF designs focus on exploiting process variations intrinsic to the CMOS technology. In recent years, progress in emerging nanoelectronic devices has demonstrated an increase in variation as a consequence of scaling down to the nanoregion. To date, emerging PUFs with nanotechnology have not been fully established, but they are expected to emerge. Initial research in this area aims to provide security primitives for emerging integrated circuits with nanotechnology. In this paper, we review emerging nanotechnology-based PUFs.
2015 40th International Conference on Infrared, Millimeter, and Terahertz waves (IRMMW-THz), 2015
A second-order bandpass frequency selective surface (FSS) for terahertz applications is experimen... more A second-order bandpass frequency selective surface (FSS) for terahertz applications is experimentally demonstrated in this paper. The proposed FSS is designed using miniaturized element unit cells that enable analysis of their frequency by an equivalent circuit model. A transmission zero is introduced in the upper stopband of the transmission response for improving the out-of-band performance. Numerical and experimental results show a harmonic-free response up to three times the passband center frequency.
A varactor-tunable second-order bandpass frequency-selective surface (FSS) for microwave frequenc... more A varactor-tunable second-order bandpass frequency-selective surface (FSS) for microwave frequencies is presented in this article. The FSS is composed of three stacked metallic layers. The wire grid in each layer in combination with metallic vias provides the bias for the varactors. This configuration eliminates the need for a dedicated bias network for the varactors, and thus avoids undesirable responses associated with the added bias grid. An equivalent circuit model together with an analytical design method is provided to simplify the design procedure of the FSS. The performance of the proposed structure is experimentally validated in a parallel-plate waveguide setup. Measurements show that by changing the varactor capacitance from 0.12 to 0.38 pF, the center frequency of the filter is tuned from 5.2 to 3.7 GHz with a consistent fractional bandwidth of 9% and with an insertion loss between 3 and 6 dB.
—In this paper, a compact microfluidic biosensor is designed based on a complementary electric-LC... more —In this paper, a compact microfluidic biosensor is designed based on a complementary electric-LC resonator coupled with a microstrip line. It is shown that by flowing water-glucose solutions with different concentrations to the sensing area, the resonance property of the resonator is modified. This measurable change in the electromagnetic property is then used to quantify the glucose concentration. A prototype of the designed sensor is fabricated and tested to verify the biosensing concept.
—This article presents a design of tunable frequency-selective surface (FSS) with miniaturized el... more —This article presents a design of tunable frequency-selective surface (FSS) with miniaturized elements. The frequency response of this FSS can be tuned by loading varactor diodes in the unit cell. The varactors are biased with a bias network composed of via holes and wire grids. An equivalent circuit model is utilized in the design process. A second-order tunable FSS prototype is designed and simulated for verification of the tunability concept. Full-wave simulations show a 40% tuning range from 5.1 GHz to 3.4 GHz with an insertion loss between 0.7–5.2 dB within the passband.
—A varactor-tunable second-order bandpass frequency-selective surface (FSS) for microwave frequen... more —A varactor-tunable second-order bandpass frequency-selective surface (FSS) for microwave frequencies is presented in this article. The FSS is composed of three stacked metallic layers. The wire grid in each layer in combination with metallic vias provides the bias for the varactors. This configuration eliminates the need for a dedicated bias network for the varactors, and thus avoids undesirable responses associated with the added bias grid. An equivalent circuit model together with an analytical design method is provided to simplify the design procedure of the FSS. The performance of the proposed structure is experimentally validated in a parallel-plate waveguide setup. Measurements show that by changing the varactor capacitance from 0.12 to 0.38 pF, the center frequency of the filter is tuned from 5.2 to 3.7 GHz with a consistent fractional bandwidth of 9% and with an insertion loss between 3 and 6 dB.
Physical unclonable functions (PUFs) are increasingly used for authentication and identification ... more Physical unclonable functions (PUFs) are increasingly used for authentication and identification applications as well as the cryptographic key generation. An important feature of a PUF is the reliance on minute random variations in the fabricated hardware to derive a trusted random key. Currently, most PUF designs focus on exploiting process variations intrinsic to the CMOS technology. In recent years, progress in emerging nanoelectronic devices has demonstrated an increase in variation as a consequence of scaling down to the nanoregion. To date, emerging PUFs with nanotechnology have not been fully established, but they are expected to emerge. Initial research in this area aims to provide security primitives for emerging integrated circuits with nanotechnology. In this paper, we review emerging nanotechnology-based PUFs.
2015 40th International Conference on Infrared, Millimeter, and Terahertz waves (IRMMW-THz), 2015
A second-order bandpass frequency selective surface (FSS) for terahertz applications is experimen... more A second-order bandpass frequency selective surface (FSS) for terahertz applications is experimentally demonstrated in this paper. The proposed FSS is designed using miniaturized element unit cells that enable analysis of their frequency by an equivalent circuit model. A transmission zero is introduced in the upper stopband of the transmission response for improving the out-of-band performance. Numerical and experimental results show a harmonic-free response up to three times the passband center frequency.
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