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In this paper we highlight the early pioneering work of Tamir and Oliner on analyzing the spectrum of waves supported by a negative permittivity slab. We show how this work relates to recent research on metamaterial slabs. We also discuss the complex modes supported by such slabs in relation to recent work on positive-index/negative-index couplers and how a single complex mode satisfies power conservation.
Multi-dimensional digital predistortion based on memory polynomial model is experimentally studied for multi-band externally-modulated radio-over-fiber (RoF) systems, in terms of nonlinearity order, memory length, maximum tolerable RF input power, and distorted signal feedback approach for model coefficients adaptation. The experimental results show that the external modulator instead of photodetector...
This paper presents a W-band LNA implemented in a 90 nm SiGe BiCMOS technology. The LNA achieves a maximum gain of 34 dB and a minimum NF of 3.5 dB at 80 GHz with greater than 25 dB gain and less than 4.5 dB NF over the full W-band. Input and output return losses are greater than 10 dB from 78–149 GHz. The circuit nominally operates from a 1.2 V supply while consuming 15.6 mW of DC power. Due to the...
In this paper, we examine the electromagnetic plane wave scattering by a uniaxial dielectric sphere using the generalized Debye series theory. With the aim of Debye series formulation, the generalized Mie series coefficients are replaced by infinite series of partial wave contributions that are diffracted, reflected and refracted following by p-1 internal reflections in the sphere. In addition to...
Distribution of electrical field gradients developing upon microwave heating glass parts immersed in an alkaline salt melt is analyzed by simulation. It is assumed that such gradients influence the process of ion exchange between the molten salt and the silicate glass immersed in it. It is shown that strong E-field gradients exist between the melt and the solid glass which could enhance ion transport...
Waveguide structures have a constrained bandwidth due to their cutoff frequencies and presence of higher order modes. Ridged substrate integrated waveguides (RSIW) are low profile, low cost and planar that can be designed for wider bandwidth. In this paper, a two-way power divider based on RSIW is designed to extend bandwidth beyond that of conventional guides. The design utilizes a developed low...
A novel compact multi-port impulse radio ultra wideband (IR-UWB) antenna is presented in this paper. Its EM simulated models is developed through properly designed magneto-electric dipole. The time-frequency domain properties of this antenna for its specific multi-port excitations are studied in details by using simulations. Its VSWR and gain patterns are obtained and verified by the measurements...
We analyze the bandwidth capability of a divider with a series RLC circuit at the isolation arm. Analytical expressions for optimal component values are given. Bandwidth limiting effect of the pad capacitances of the chip resistors is analyzed. These parasitic capacitors are compensated by the proposed structure. Broadband characteristic of the new divider is verified by experimental results.
Two new interconnects between coplanar waveguide (CPW) and substrate integrated waveguide (SIW) are introduced and studied. Contrary to previously published interconnects, the new ones are shorter and require less space on the printed-circuit board. Thus they are ideally suited for dense packaging and integration. The first one is a regular interconnect that runs the slots of the CPW directly into...
This work presents an application of a planar electromagnetic band gap (EBG) structure with a perspective product implementation in the back of the mind. The focus is on the integration of such structure under the constraint of space and system coexistence. It is discovered that it is possible to achieve simultaneously both the enhancement of the antenna radiation efficiency and the shrinking of its...
A new class of combiners for base stations of mobile communications is introduced. This combiner allows to share two antennas between two base stations which both use an additional diversity channel in the receiving band. To achieve this result, classical combiners require at least 4 filters and one 3dB divider. With the new solutions only 2 filters are needed, resulting in a substantial reduction...
Presented herein is the first ever hardware based methodology for collision avoidance of multiple, frequency doubling transceivers. Frequency doubling transceivers have many advantages over other passive RFID systems, including their simplicity, size, and read range. The drawback of frequency doubling transceivers is the lack of a method for uniquely identifying a single tag when multiple tags are...
A surface impedance implementation of the skin effect for a finite difference frequency domain solver is discussed. Boundary conditions are modeled as current source elements at the surfaces of conductors of the susceptance element equivalent circuit model for the microwave structure. A Taylor series approximation is used to expand the frequency term in the skin effect model, such that multi-point...
A multi-tap microwave photonic filter (MPF) with its center frequency tuned by a single parameter is proposed and demonstrated based on polarization modulation. By simply adjusting the amplitude of a sawtooth wave signal to a polarization modulator, the MPF is tuned with the shape and the free spectral range (FSR) unchanged. The proposed system has advantages in terms of simple operation, fast tunability...
Microwave-enabled exfoliation of graphite oxides has been recently shown to be capable of quickly producing graphene sheets of larger size and with fewer defects with the potential for low-cost mass production. In this paper, we investigate microwave heating of graphite powder in a waveguide reactor using multiphysics macroscopic modeling and experimentation. High heating rate and strong non-uniformity...
This paper presents an X/Ku-band bi-directional true time delay T/R chipset in 0.13 µm CMOS technology for wideband phased array antenna. The T/R chipset comprises of wideband bi-directional distributed gain amplifiers (BDGA), a 7-bit true time delay (TTD) circuit, and a 6-bit digital step attenuator. The tuning bits are included in TTD (2-bit) and DSA (2-bit) for the amplitude and group delay error...
This paper presents the first vibration mitigation technique for evanescent-mode cavity filters. The effect of vibration is substantially reduced by over 20 dB by injecting a voltage signal on the bias of the tuning piezoelectric device. The vibration is measured by an accelerometer and the frequency and amplitude of this signal is chosen based on the analysis of the measured acceleration. The proposed...
In this paper, a multi-band bandpass filter (BPF) based on a novel architecture and design method is presented. Very uniquely, its multi-band frequency response is synthesized by giving the transmission- and reflection-zero frequencies. To verify the proposed method, a miniaturized dual-band BPF is implemented using low-temperature co-fired ceramic (LTCC) technology. The size of filter is 2.0 mm ×...
Microwave rapid and selective heating is successfully applied to produce freestanding capsule-less doses of powdered beans or leaves for hot beverages preparation. 1 or 3-person doses, suitable for use in conventional hot beverage preparation machines are obtained in less than 5 seconds, without any additives except for water. Microwaves at 2.45 GHz are applied to allow shape retention and surface...
Different resonant particles are analyzed for a coplanar sensor device that is able to operate in two modes: sensing dielectric properties of organic tissue and performing thermal ablation therapy. For an efficient transfer of the electromagnetic energy into the tissue, a careful analysis of how the ablation zone is affected by the different resonator particles is performed. The investigated resonant...
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