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In this paper, a LC (inductor capacitor) wireless gas sensor is demonstrated for the identification of volatile organic compounds (VOC's) in the air environment. A near-field LC resonant tank consisting of an interdigitated capacitor fabricated on a porous flexible substrate coupled with an inductor coil is used as a sensor and its resonance is interrogated using an external pick up coil. The porous...
Regarding the power quality problems, harmonic voltages and currents are a consequence of electric nonlinear loads. A boost converter is one of the most popular topology in a medium power unit in order to correct the power factor and reduce harmonic currents. However, this circuit is a little bit complicated in the power stage and control design. As in the sinusoidal current-tracking technique, the...
Regarding the great advantages of impedance source converter topologies, research trends based on conventional Z-source inverter (ZSI) are much more interesting. However, it is very complicated because such a model is forth-order system. The higher order model remains a large obstacle for switching power converter design of various applications. This paper investigates the feasibility of reduced order...
Dead-time is added into pulse width modulation (PWM) signals to prevent a short circuit of the DC bus. However, adding the dead-time can cause higher total harmonic current distortion (THDI). In order to minimize this problem, this paper proposes a simple dead-time compensation technique for single-phase full-bridge PWM rectifier, which is used in power factor correction (PFC) application. The proposed...
In this paper two metamaterial structures are presented for the design of millimeter and terahertz (THz) bolometers. The first design is composed of U-shaped resonant structures grouped together to achieve strong absorption and wide-bandwidth properties. The second design is a hybrid between a serpentine and a spiral structure which provides strong absorption over a much wider bandwidth (> 100...
In this paper, a compact multi-use volatile molecular sensor with high sensitivity is demonstrated. The sensor design is based on a planar metamaterial-inspired modified split ring resonator with open gap (OmSRR) forming an effective inductive-capacitive (LC) resonant tank having high quality (Q) factor with operating frequency near 7.4 GHz. Between two ring structure a capacitive gap is designed...
Carbon fibers are utilized in the fabrication of terahertz (THz) polarizers on polymer substrates. Commercially available fibers are aligned on a polymer substrate through a dip coating process. During the dip coating process, the fibers align in parallel to each other on the substrate. A multilayer structure is achieved using this approach. This fine alignment and multi-level stacking leads to THz...
Design and fabrication of dielectric lenses for terahertz (THz) focal plane arrays are presented in this paper. Lenses are designed using optical lens and ellipsoid function theory in the terahertz range (centered at f = 300GHz). In order to enhance coupling to planar circuits on wafer, two types of lenses are considered: modified hemispherical, such as extended hemispherical and hypo-hemispherical...
This paper presents a high-quality factor (Q) X-band oscillator that utilizes a planar metamaterial-inspired modified split ring resonator (mSRR) in its design. The mSRR of this paper has a quality factor above 300 at 7.89GHz. Design of an X-band oscillator circuit is presented in this paper. In comparison to dielectric resonators, metamaterial resonators can prove to be reliable under harsh conditions,...
This paper presents a new compact bandstop filter designed using a novel periodic structure. The proposed periodic resonant structure is based upon a split ring resonator (SRR) design, and it shows the characteristics of a bandstop LC resonator. The designed bandstop filter has the desired characteristics such as wide bandwidth, sharp and deep skirt performance and small physical size. Details of...
A modified split ring resonator (mSRR) is incorporated into a compact folded dipole antenna structure to lower the resonant frequency of the circuit. The resonance characteristics of the antenna are further improved by incorporating a solid ground plane. By integrating a varactor diode as an integral part of the antenna, the resonance characteristics of the antenna can be electronically tuned. A tuning...
In this paper, a broad band reconfigurable phase shifter designs utilizing composite right/left-handed transmission line (CRLH TL) metamaterials is demonstrated for X-band applications. Metamaterial unit cells are designed that allows seamless integration of active devices (varactor diodes) in order to achieve reconfigurability. Design equations and properties with arbitrary phase, band-pass characteristic,...
In this paper, two microstrip transmission line based metamaterial structures (sub-wavelength sized resonators) are designed and implemented in near field sensing of dielectric materials. One structure is designed for band-stop and the other for band-pass performance in the X-band region. These resonators load the microstrip lines on both the sides. Resonator on one side is used in interrogation of...
In this paper, a spoof surface plasmon assisted antenna is paired with a metamaterial enhanced bolometer structure in the formation of a THz focal plane array pixel. The antenna element focuses the electromagnetic wave onto the bolometer element and the bolometer detects this incident power through resistance change. Numerical analysis was performed in order to simulate the plasmonic structure at...
In this paper, THz circuits and sensors are designed and experimentally implemented using a cost effective plastic injection micromolding process. Plastic resin, having low refractive index and loss in THz region, was used as the base material to manufacture THz circuits. Periodic structures such as photonic bandgap (PBG) were utilized to design THz circuits and sensors. Numerical simulations were...
A novel power meter operating from 0.1 to 0.2 THz is presented. The power meter has utilized a thin-film metamaterial inspired absorbing layer. This absorber has the desired characteristics such as ultra-wide bandwidth and strong absorption. In a bolometer-like measurement setup, it functions as a wideband high-responsivity THz detector. The absorbing layer consists of a low loss thin dielectric membrane...
In this paper, plastic microinjection molded WR-3 rectangular metalized waveguides are demonstrated. The process is simple to implement and allows fabrication of complex 3D structures. Different types of waveguide filters are fabricated using this process and measured results are reported. Simulation results show that filters with good performance in the millimeter and sub-millimeter wave range can...
In this paper, a new metamaterial (MTM) unit cell implemented in a microstrip transmission line configuration is proposed. Reconfigurable metamaterial-based Composite Right/Left Handed (CRLH) microstrip transmission line, with one-side etching and no via, is presented here for the first time. As a result, it is easier to fabricate and more convenient for integration. By incorporating varactor diodes,...
In this paper, microstrip-based spiral structured artificial magnetic media (metamaterial) coupled with microfluidic channel is experimentally demonstrated for sensing applications. It is found that the resonant frequency and the amplitude changes due to dielectric loading from the introduction of chemical substances in the microfluidic channels. Different concentrations of water — methanol and water...
In this paper, thin metamaterial-inspired structures are investigated for wide-band absorption of stray signals for THz packages. The absorber itself consists of a low-index, low-loss dielectric sandwiched between a patterned, two-dimensionally periodic, thin metallic layer, and a metal backing. Numerical simulations were performed using both the finite element (FEM) and finite-difference time domain...
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