Muhammad Faeyz Karim

A Reconfigurable Micromachined Switching Filter Using Periodic Structures

In this paper, a reconfigurable filter using micromachined switches is designed, fabricated, and experimented. An equivalent-circuit model is derived for the reconfigurable cell structure. Extracted parameters show the characteristics of both bandpass and bandstop filters, which can be accurately analyzed using circuit analysis. Coplanar waveguide transmission lines for the reconfigurable filter are also analyzed. The bandpass filter is formed by cascading the unit cell structure. This bandpass filter can be switched to bandstop filter using the micromachined switches and p-i-n diode. Dispersion characteristics are obtained to investigate the electromagnetic wave behavior within the unit cell using Floquets theorem. Measurement results with micromachined switches show that insertion loss is 1.55 dB for the bandpass filter whereas band rejection level is >20 dB and the insertion loss in the passband is 1.2 dB for the bandstop filter. With the p-i-n diode, the insertion loss is 2.1 dB and the 3-dB bandwidth is 5.2 GHz for the bandpass filter, the 20-dB rejection bandwidth is 5.3 GHz, and the insertion loss in the passband is 1.6 dB for the bandstop filter.

A Novel Reconfigurable Filter Using Periodic Structures

In this paper, a reconfigurable filter is realized using electromagnetic bandgap structures (EBG) which can be switched from bandpass to bandstop filter at the same frequency by PIN diodes. A unit model for the reconfigurable filter is derived by equivalent circuit approach and full wave electromagnetic simulation is used for extracting the values of the lumped elements. The extracted parameters show that the bandpass and bandgap effect of the EBG cells. The dispersion diagram is obtained for the structure by combining the commercial software and the Floquets theorem. The PIN diodes are used to switch from bandpass to bandstop filter. The measurement results show that the insertion loss in bandpass filter is around 2.1 dB and the 3-dB bandwidth is around 5.2 GHz which is suitable for wideband applications. For the bandstop filter, the 20 dB rejection bandwidth is 5.3 GHz and the insertion loss in the pass band is 1.6 dB

A tunable bandstop filter via the capacitance change of micromachined switches

A tunable bandstop filter applying the capacitive change of micromachined switches is designed, simulated and fabricated. The filter is realized by incorporating electromagnetic bandgap structures with the micromachined switches. These micromachined switches are used as high contrast capacitive elements between the coplanar waveguide ground plane and the signal line to tune the frequency. A new approach for finding the propagation characteristic of the periodic micromachined switches is determined by the dispersion behavior. Different types of parametric analysis are also investigated for the micromachined switches. The surface micromachining fabrication process is employed on the high resistivity silicon substrate to fabricate the filter. The measurement results for the tunable bandstop filter reveal a tuning range from 19 GHz to 17.3 GHz. The lower passband insertion loss is 0.7–2.2 dB and the 20 dB rejection bandwidth is 5.5 GHz.

Integration of SiP-Based 60-GHz 4

An integrated system-in-package-based 60-GHz 4 × 4 antenna array with CMOS on-off keying (OOK) transmitter and low-noise amplifier (LNA) is investigated. The 4 × 4 circular polarized array exhibits a wide impedance bandwidth (VSWR <; 2) and 3-dB axial ratio bandwidth of over 8 GHz using a strip line sequential rotation feeding scheme. It has a beam-shaped pattern with a 3-dB beamwidth of 20° and a peak gain of 16.8 dBi. The modulators in 90-nm CMOS includes 60-GHz oscillators and switchable amplifiers to achieve the OOK modulation. The key features of the circuits are small power consumption and size. By applying a bond wire compensation scheme, the LNA and 60-GHz CMOS modulator are successfully integrated into the low-temperature co-fired ceramic package with 2-mil 500-μm-long bond wires. The measurement results for the antenna array with LNA shows a peak gain of ~ 35 dBi. The 60-GHz CMOS modulator is tested at a data rate of 2 Gb/s and the bit-error performance of the system is also demonstrated. The energy usage of 60-GHz modulator at 2 Gb/s is only 13.2 pj/bit for the modulator.

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A MEMS based tunable bandstop filter using electromagnetic bandgap (EBG) structure is proposed in this paper. A tunable band-stop filter (BSF) has been designed with flat response at a selected frequency by incorporating microelectromechanical systems (MEMS) bridges. An equivalent circuit model for the tunable bandstop filter is derived and its parameters are extracted by using commercial software. High resistivity silicon substrate and MEMS surface micromachining process are employed. The measurement results for the tunable band stop filter reveals a tuning range from 19 GHz to 17.3 GHz. Additionally, low-pass-band insertion loss is found to be 1.3- 2.4 dB.

4 Antenna Array With CMOS OOK Transmitter and LNA

A photonic bandgap (PBG) band-stop filter with flat response in a selected frequency band is designed in this paper. Two kinds of equivalent circuits for the proposed structure are derived and its parameters are extracted by using electromagnetic field software ADS. High resistivity silicon substrate and microelectromechanical systems (MEMS) surface micromachining process are employed. The measurement results revealed a 20 dB stop-band that has a width of 13.2 GHz, without ripples in the full band. The lower pass-band insertion loss is less than 2 dB and the higher pass-band insertion loss is less than 4.5 dB, without traces of ripples.

MEMS-based tunable bandstop filter using electromagnetic bandgap (EBG) structures

A MEMS based tunable bandstop filter is proposed for the wireless sensor networks. A tunable band-stop filter (BSF) has been designed with flat response at a selected frequency by incorporating microelectromechanical systems (MEMS) bridges. An equivalent circuit model for the tunable bandstop filter is derived and its parameters are extracted by using commercial software. High resistivity silicon substrate and MEMS surface micromachining process are employed. The measurement results for the tunable band stop filter reveals a tuning range from 19 GHz to 17.3 GHz. Additionally, low-pass-band insertion loss is found to be 1.3-2.4 db

MEMS-based photonic bandgap (PBG) band-stop filter

In this paper, a double tapered fractal electromagnetic bandgap (DT-FEBG) technique in planar CPW structure is proposed and analyzed. The DT-FEBG structure of CPW not only improves the pass band performance but also generates two distant band-gaps. The fractal structure is realized by replacing the etched rectangular holes with a Minkowski loop generator. High resistivity silicon substrate and MEMS surface micromachining process are employed. The DT-FEBG structure shows insertion loss of less than 1.3 dB and the stop band rejection of around 44 dB.

Micromachined tunable bandstop filters for wireless sensor networks

A novel Composite Right/Left Handed (CRLH) material based Frequency Selective Surface (FSS) for enhancement in performance of microstrip antennas has been designed and simulated. The FSS structure is realized by repeating an unbalanced CRLH unit cell in two dimensional form. The bandgap region of the unit cell extends from 2.4GHz to 6GHz. A microstrip patch antenna operating at 2.34GHz is designed on one side of the substrate and stacked up together with the CRLH based FSS. The performance of the patch antenna with and without the FSS was compared. An increase in gain of 1.9dBand an increase in the front-to-back ratio of 4.9dB was observed.

Fractal CPW EBG filter with nonlinear distribution

In this letter, we report the experimental demonstration of a dissipative self-sustained optomechanical resonator on a silicon chip by introducing dissipative optomechanical coupling between a vertically offset bus waveguide and a racetrack optical cavity. Different from conventional blue-detuning limited self-oscillation, the dissipative optomechanical resonator exhibits self-oscillation in the resonance and red detuning regime. The anti-damping effects of dissipative optomechanical coupling are validated by both numerical simulation and experimental results. The demonstration of the dissipative self-sustained optomechanical resonator with an extended working range has potential applications in optomechanical oscillation for on-chip signal modulation and processing.In this letter, we report the experimental demonstration of a dissipative self-sustained optomechanical resonator on a silicon chip by introducing dissipative optomechanical coupling between a vertically offset bus waveguide and a racetrack optical cavity. Different from conventional blue-detuning limited self-oscillation, the dissipative optomechanical resonator exhibits self-oscillation in the resonance and red detuning regime. The anti-damping effects of dissipative optomechanical coupling are validated by both numerical simulation and experimental results. The demonstration of the dissipative self-sustained optomechanical resonator with an extended working range has potential applications in optomechanical oscillation for on-chip signal modulation and processing.