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This paper presents a new wafer level packaging (WLP) technique that combines thin, low cost organic layers with high performance MMICs. More specifically, we present a GaAs-based single stage amplifier covered with layers of a low loss liquid crystal polymer organic material. It was observed that the RF performance of the MMIC is virtually unaffected by this technique unlike conventional packaging...
This paper presents a MEMS surface micro-machined varactor. The dynamic range of this class of varactors is governed by pull-in instability which is ideally one-third of the initial gap between the two electrodes. This paper presents a simple T varactor, whose pull-in stability and hence its dynamic range are increased by applying two independent voltage sources. We introduce an electromechanical...
A new approach is proposed for designing a decoupling feeding network for phased arrays. The proposed approach results in significant hardware savings and enables to match each of the input ports individually and independently of the excitation.
New requirements are formulated for phase shifters used in phased-array antennas: 1) small power in biasing networks, 2) higher microwave power, 3) low production cost. Reflection type phase shifters on ferroelectric tunable capacitors in combination with hybrid junction form a transmission type phase shifter. Two ferroelectric capacitors are connected in parallel with respect to RF voltage and in...
This paper considers Doppler-polarimetric radar methods in application to observing distributed targets. Examples of typical distributed targets are meteorological objects. For instance, among wide variety of meteorological objects, such targets as clouds with precipitation are considered. Developed mathematical models of Doppler-polarimetric reflections from distributed targets as rain and clouds...
The transmission and receiving of several channels via a single antenna is a long standing problem. We have developed a multi-channel coupler in the VHF frequency range enabling to reduce the number of antennas to one third of channels number used at one time. The system is based on a meander stripline used for each coupling channel. The channels were matched simultaneously to a single antenna using...
We investigate the use of synchronized superposition-modulation for increasing spectral efficiency of frequency division multiple access systems such as the long-term evolution extension of UMTS. We present the basic concept and depict results for an arbitrary two-user scenario. In Addition, a method of optimizing constellations for multiple users is defined based on maximizing the sum-rate mutual-information...
[Summary form only given]. Wideband, large phased array antennas, using analog control for angle scanning, require true time delay (TTD), rather than phase shifters, to avoid squint and other impairments in both the temporal and spatial domains. While digital beamforming may eventually become a viable solution for such high-end systems, photonic technology can currently provide the required TTD capabilities...
This review presentation will look at the unique requirements for the antenna and beamformer for today's wideband systems which need high resolution. Unlike quasi monochromatic phased array technology, when dealing with wideband phased arrays, the designer needs to take into account the transfer function of the element as a function of scan angle, redefining the phased array problem and leading to...
Traveling wave tubes (TWTs) remain the amplifiers of choice in many ground and space-based applications requiring the production of broadband high frequency microwave and millimeter wave power with high efficiency. All modern TWTs are designed using sophisticated computer-based design tools that are based on the fundamental physical laws governing the emission, transport, interaction, and collection...
A microstrip circuit is matched by using three parasitic elements, where by "parasitic" we mean that there is no physical connection between the matching elements and the main circuit. A 1:2 microstrip divider is used as an example, for which two parasitic elements are located on the output strips of the divider and a single matching element is located on the input strip. The divider was...
Algorithms for point target detection in hyperspectral images use the inverse covariance matrix in order to separate a detected pixel from it surrounding noise. The inverse covariance matrix can be implemented from all the pixels or from the close surroundings of the examined pixel. We compare the different methods and conclude which method brings the best results.
This paper reports analysis and design of bandstop filter utilizing E-shaped dual mode resonator. The basic structure of the bandstop filter consists of E-shaped resonator parallel to microstrip transmission line and an open stub inverter. Parametric analysis is carried out using micro-stripes software and the design is optimized to get stop band with high rejection level at 6 GHz centre frequency...
In this work describe some new functional possibilities of chirp ionosonde in addition to building of oblique sounding ionograms. It is separation of signal and noise on output of receiver, detection of spectrum concentrate disturbance, rejection of spectrum concentrate disturbances and cleaning ionograms from strange signals, measuring characteristics of signal and noise, reconstruction of signal...
The design of commercially packaged LNA at X band frequencies necessitates the examination of different circuit aspects and poses some significant challenges. The selected package and the resulting parasitic need to be carefully examined as they have a significant impact on the design. While parasitic can easily degrade LNA performance, package's high Q inductance can be leveraged to lower input losses...
Presented paper is devoted to theoretical modeling and experimental investigation of transferring of initial phase of low frequency oscillations with modulation of carrier oscillations in separate high frequency link from one part of testing link to another. The main goal of this investigation is the determination of influence of phase stability and amplitude one of separate high frequency link on...
Radial 1:6 microstrip divider is proposed. The divider is based on tapered horizontal and vertical strips and has a 50 ?? SMA connector at the input port and 50 ?? SMA connectors at the output ports. The divider was simulated and measured, showing a bandwidth of 33% for SWR = 2, low insertion loss and high accuracies of output amplitudes and phases. Very good agreement between simulation and measurement...
This paper presents an original 60 GHz architecture for ultra-wide band (UWB) radio-over-fiber (RoF) systems to increase both the transmission distance and the high data bit rate. With a central station (CS) and a base station (BS), this architecture allows to send through an optical fiber both a subcarrier microwave signal and UWB baseband data by using a wavelength multiplexer. At the BS, the carrier...
We present a UWB two-way communication system with novel PHY and MAC layers, for low-rate communications with multitude of low-cost devices in ultra low power consumption. The system features a novel multiple access protocol called interleaved impulse radio. In this simple protocol the transmission is done in short bursts of about 100 ns with large gaps between them. During the gaps other users can...
A high gain 3-arm spiral antenna with planar unbalanced feed is proposed. It is shown that the traditional characteristic of spiral antenna apply to this type of spiral antenna. A very wide band frequency range and circularly polarization are achieved. Through numerous numerical simulation, it was determined that the radiation efficiency of the antenna can be improved significantly once the line width...
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