Abstract: Problem statement: Low-Noise Amplifiers (LNA) are very indispensable components in the designof numerous types of communication receivers employed in microwave technology. This paper is presents the design and development of low bias(Vce = 8v, Ic =10 mA) single stage low noise microwaveamplifier operating in 1.5GHZ frequency range, Gain 13dB ± 0.5dB, input/output return loss < -10dB, noise figure ≤2.0dB and used of Agilent AT-41486 bipolar junction transistor. Approach: The principal design target is to obtain a minimum noise figure while concomitantly achieving a maximum gain by presenting the optimum noise impedance (Z opt ) which is
Low noise microwaveamplifier is a very important component in receiver applications especially when it is required to have preamplifier with as low a noise figure as possible and details of a low noise amplifierdesign can be found in many texts -. A detailed explanation for CMOS low noise amplifierdesign with different optimisation techniques was presented by Nguyen et. al. . Generally it is not possible to obtain both maximum gain and minimum noise figure therefore a trade off exists between noise figure and gain. Therefore the task is essentially solving a multiobjective optimization problem. Similar work, designing a CMOS operational transconductance amplifier, was done by converting the constrained optimisation problem into an unconstrained one by Bennour et. al. . Recently memetic algorithm was applied to design a low noise microwaveamplifier by some researchers . In this work, microwave low noise transistor amplifierdesign is done using particle swarm optimization technique.
This paper presents two low noise amplifier (LNA) circuit topologies for ultra-wideband wireless communications in 0.13 μm PHEMT GaAs technology. They are with source inductive degeneration and source grounded, respectively. The simulation results show that the LNA involving source inductor possesses good performances at 120MHz-3GHz. Its noise figure(NF) and voltage standing wave ratios(VSWRs) are less than 1.173dB and 2, respectively, while the maximum gain of 12.75dB is achieved with 0.63dB flatness. In contrast, the other LNA provides a decreasing gain varying between 10.992dB and 11.964B in a wider frequency range of DC-3.4GHz. NF and VSWRs are better than 1.287dB and 2, respectively.
Body sounds gives lots of information about human health. There are still opportunities in these fields for further improvements. First of all, there is still a room for easy, ergonomic and cheap electronic devices for varying fields of medicine. Secondly, with new technologies ofwireless connections, internet communication, there are some new fields of development.
The geoquorums approach, for implementing atomic read/write shared memory in mobile ad hoc networks based on associating abstract atomic objects with certain geographic locations. In the previous sections the following points are discussed and for summary, the existence of focal points as geographic areas that are normally "populated by mobile nodes" is explained, the geoquorums algorithm uses & quorum –based strategy in which each quorum consists of a set of focal point objects. The quorums are used to maintain the consistency of the shared memory and to tolerate limited failures of the focal point objects, which may be caused by depopulation of the corresponding geographic areas. Overall the new geoquorum algorithm efficiently implements read/write operations in a highly dynamic, mobile networks .this application is implemented using geoquorum algorithm. This algorithm consists of two independent components: the focal point emulator, which implements the focal point object model in highly dynamic environment, and the operation manager, which is a quorum- based algorithm for read/write shared memory. By replicating data at multiple focal point objects and performing read and write operations on quorums of focal point objects, the operation manager ensures that the data is maintained reliably and consistently. The operation manager relies on the variable type of the focal point objects, which we call the put / get variable type. These objects support specially defined operations, put / get and config / reconfig that allow clients to send information to the objects and retrieve information from the objects also switching between the available put / get quorums thus exchanging information .each focal point supports a local broadcast service (LBcast service),which provides reliable totally ordered broadcast. This service allows each node in the focal point to communicate reliably with every other node in the focal point. The mobile nodes also depend on a global message delivery service, Geocast. The Geocast service delivers a message to a specified destination point in the plane and every node within a certain radius of that destination.
Analog design has not been automated to a great extent so far, mostly because of its overwhelming complexity. On the other hand, with analog designs becoming increasingly complex each day, there is a pressing need for analog circuit design automation. Besides that, recent works - show a renewed interest in filters. Many traditional techniques for direct synthesis are available in the literature . However, in modern applications ─ wireless communication systems, for example - the rigorous specifications of filters demands by new methodologies that will be effective to aid the human designers to find structures of filter circuits capable of providing high frequency selectivity, and group delay equalization in order to meet efficient spectrum utilization and to reduce the distortion in a digital data transmission .
NE of the most important and widely used analog building block is the operational transconductance amplifier (OTA). This new class of operational amplifier (OP-AMP) has not only all the advantages and applications of the conventional OP-AMP, however, is has some extra advantages and applications. Apart from differential inputs, it contains additional control terminal which enhance its flexibility and application domain. The other advantages of OTAs include large bandwidth, large dynamic range, no excess phase issues, flexibility and tunability and realization of high integration level integrated circuits. The realization of CMOS based OTA has resulted
Nowadays communication is very important to society, leading to an exponential growth in the wireless market. As wireless connectivity arrives to the consumer’s market the main goal of the Integrated Circuit (IC) manufacturers is to provide low cost solutions. The Power Amplifier (PA) is a key building block in all Radio Frequency (RF) transmitters. In order for the manufacturers to reduce the costs of communication devices and allow full integration (System-on-Chip (SoC)) it is desirable to integrate the entire transceiver and the PA in a single Complementary Metal-Oxide-Semiconductor (CMOS) chip. The CMOS technology enables such cost reduction while being able to operate at high frequencies.
The microwave absorbers are frequency independent materials and are designed according to the range of frequency. This relation is established in Fresnel’s equation. Hence an analyis on the effect of frequency on absorber design is conducted for various microwave absorbers from the best obtained results. As per the literature above suggested a microwave absorber for TM polarization and for an angle of 45 is designed using three different number of layers over three ranges of frequency S and C band (2-8GHz), X band (8-12GHz) and Ku band (12-18GHz). Various experiments on N=2 layers absorbers have been designed and analyzed in earlier literature . The increase in the number of layers have shown improvement in obtaining the minimum reflection coefficient. Hence this analysis will help to choose microwave absorbers according to specific frequency band for the required application. Also this frequency range is widely used in fields of military and civil applications. Based on the thickness specification, the absorber can be choosen. The number of layers are considered excluding the PEC layer and it is considered as N+1th layer which acts as the substrate for every design. This experiment is carried out using improvised particle swarm optimization for a changing dimension which is the number of layers and the material used. Design number 12 to 14 correspond to absorbers with N=4 layers. Design numbers 15 to 17 correspond to absorbers with N=5 layers and design numbers 18 to 20 correspond to absorbers with N=6 layers. Based on the number of layers N the minimum reflection coefficient and its thickness is calculated and presented below.
Abstract—Recent studies proved that certain electronic active circuits are capable to exhibit simultaneously a negative group delay (NGD) and amplification in microwave frequency bands. One of the simplest topologies generating this counterintuitive NGD function effect is formed by a series RLC-network in cascade with a transistor. By using this cell, similar to the classical electronic functions, dual-band NGD microwave devices with loss compensation possibility can be designed. Theoretic demonstrations concerning the theory of the NGD circuit considered are presented. The dual-band NGD concept feasibility is concretely illustrated by an example of EM/circuit co-simulations. So, in frequency domain, dual-band NGD with minimal values of about –1 ns was observed simultaneously within two frequency bands centered at about 1.05 GHz and 2.05 GHz. To highlight the functioning of the hybrid device considered, time-domain analysis showing the RF/microwave signal advancement is performed. As application, the concept investigated can be envisaged for data synchronization in multi-channel wireless communication systems eventually degraded by undesired EMI effects.
Abstract—Wireless data usage is growing now faster than ever before. In order to attend the increasing demand for wireless services and considering that frequency spectrum is a scarce and expensive resource, wireless are required to operate as efficiently as possible. In this context, the applicationof mathematical optimization methods in the study and designof key function- alities ofwireless systems has acquired great relevance. This papers surveys some applications of optimization methods to wireless communications problems. Among them, game theory and majorization theory have got increasing attention in the last few years and are described in some more details. An applicationof optimization methods to solve a concrete problem in modern wireless communications, namely, the maximization of the ergodic capacity of a Coordinated Multi-Point system with statistical Channel State Information at the Transmitter is also provided.
There is also a major advantage that makes optical fiber the most e fficient type of communication channel for this particular application. It can be used in environments with large Electromagnetic Interference and Radio-Frequency Interference which is the case of the surrounding environment of the LHC, where radiation is not the only source for disturbance or system failures: the electromagnetic environment in the tunnel and service areas is rich in interference sources . Hence, the use of optical fiber implies the existence of an Optical Receiver, which consists of the blocks mentioned earlier plus an off-chip CDR circuit (which is not to be implemented in this project). Although there are many wideband Optical Receivers available in the market there is a need for a special circuit. Due to the beam interactions with residual gases, collimators or other equipment in the experiences, there is a lot of ionizing radiation with a broad energy spectrum. This ionization can permanently damage the electronic components by altering the device parameters. For example, it can change the value of the transistors’ threshold voltages and leakage currents and, in the case of the Photodiode, it can brutally increase its Direct Current (DC) leakage current, leading to a decrease in the Photodiode bias voltage (due to high voltage drops in the biasing circuit). The permanent changes in the electronic devices caused by radiation are called Total Ionizing Dose (TID) effects. Additionally, radiation can also cause exceptional and isolated events. These are called Single-Event Effects (SEE), such as: Single-Event Upsets (SEUs), Single-Event Functional Interrupts (SEFIs), Single-Event Transients (SETs), and Single-Event Latchups (SELs) .
Abstract: The primary objective of the project is to create a prototype of a purely air powered motorcycle by retrofitting its internal combustion engine to run on compressed air. Firstly, the conventional spark plug was replaced with a solenoid valve. The solenoid valve was initially actuated using a reed switch and magnet duo, but then later replaced with an optical crank position sensor circuit due to reasons that include lack of control over the amount of air injected during each stroke and also for more precise control over the opening and closing of the valve. The torque, brake power, indicated power, air consumption rate of the engine under load are calculated. Separate mounts for the modified engine and the cylindrical storage unit are designed and analysed using Catia v4. Also, possible ways of future scope of the prototype are mentioned.
The first part of this documents focuses on identifying suitable demo applications. The WP1- D1  has shown that CORTEX is addressing a diverse range ofapplication types which have different requirements. In particular, it was identified that the covered application scenarios require different degrees of autonomy, consistency and cooperation. However, these applications will commonly involve only a subset of such characteristics. Hence, we have selected two demo applications which altogether cover all the main CORTEX characteristics. The control car scenario focuses on real-time ad hoc environments whereby cars are able to operate automatically to avoid collisions. Complementary, the smart room application pays more attention to the intelligent behaviour of sentient objects in which the conditions of the room are automatically set according to the preferences of the people present in the room. The second part of the document presents a middleware architecture whereby different partner’s contribution are integrated. Such platform makes also possible to reuse the system architecture in diverse applications. More concretely, the architecture will be used for the support of the two demo applications. Moreover, the middleware allows us to provide configuration and reconfiguration support to achieve adaptation when unexpected changes are introduced to the environment. The middleware is basically conformed by a number of component frameworks (CFs). The publish/subscribe CF realises the CORTEX event model . The functionality of the control engine of a sentient object is provided by the context CF. Services can be dynamically discovered by the use of the service discovery CF  . Facilities for multicast in ad hoc environments are then provided by the multicast CF. The TCB facilitates the detection of timing failures and support for QoS adaptation is provided by the coverage CF . Lastly, the resource management CF controls the resources used by all the CFs . Finally, the software and hardware infrastructure support for the demo applications is introduced. The designof the two demo applications is presented as well and an overall summary and some concluding remarks are drawn.
The design uses a low permittivity dielectric supporting the inverted radiating E-shaped patch above a ground plane with an air-filled substrate sandwiched between them. The design meets the broadband bandwidth requirement of better than 15.42% at 14-dB return loss. Apart from maintaining the broadband characteristic of the antenna, the thick air-filled substrate sandwiched between the ground plane and the patch eased the probe feeding to the patch. In addition, by employing the air-filled substrate, the substrate thickness can be adjusted easily in the design by adjusting the spacer and it is more cost effective.
query packet which will be discarded by node C since it has already be involved in the forwarding process, and node H should discard the duplicate query packet received (the last query packet sent by node D or node G); in e) the forwarding process continues and for the particular case of node F, since it has one neighbor node which runs App. A (node B), and it does not know that node B had already forwarded this query packet, node F will forward the query packet, which should be discarded by nodes E and J because they do not run this application and do not have neighbors who support it; nodes B and G will also discard the packet because they have been evolved earlier in the process; also, node K having at least two neighbor that support App. A will forward the packet, which should be discarded by nodes G and J; Node L should get the query packet from both node H and node K, and should discard the last packet received; finally, in f) node O receives the packet from node K and since it has one neighbor running his application (node P) it will forward the packet; node N should discard it, and node P will most likely receive two query packets, one from node L, and the other from node O, and since it has no more neighbor nodes which may be evolved in the forwarding process, the process ends here. At the end, the query packet issued by the sink node A has arrived to all the correspondent nodes.
The design relays on a common source transistor with negative feedback configuration where a feedback resistance is used to minimize the dc current and voltage variations in the bias circuit. Under small-signal operation, the LNA is linear and, consequently, S-parameters can be used to characterize it . The approach starts by the stabilization of the transistor adding resistances on the gate and on the drain which are the input and output of the active device, respectively. These resistances are the same used to the transistor’s biasing. Then it is found the impedance that the active device sees at the input because the optimum impedance for lower noise is not equal to the conjugate of input impedance as can be seen in Fig. 1, in other words, there is a tradeoff between low noise and input matching.
FACTORIAL DESIGN EMPLOYED FOR MICROWAVE-ASSISTED DIGESTION OF BEAN SAMPLES. The use of factorial design was evaluated for optimization of focused-microwave-assisted digestion of bean samples. Calcium, Fe, Mg, Mn and Zn percentual recoveries were determined in digestates after focused-microwave-assisted digestion according to factorial design procedures. A cavity microwave digestion was carried out to certify the elemental compositions obtained. The accuracy was checked using a standard reference material, the NIST SRM 8433 - Corn Bran. Results are in agreement with certified values at the 95% confidence limit when the Student t-test was used. Volumes of nitric and sulfuric acid, temperature, and the interplay between HNO 3 and H 2 SO 4 initial volumes were significant variables according to P-values in the analysis of variance (ANOVA).
This paper discusses and suggests some ideas and necessary changes in implementation of virtual trainer in an organization. With the invention of new technologies like high speed computer networks and multimedia computers, there is an increasing awareness that direct face to face teaching is not the only possible mode of training methodology in an organization. There is a demand for preparing high quality multimedia training material across all faculties, which can be used by learners of the course who either cannot attend the live lectures or prefer to study in an off-line mode. Assignments, Seminars and evaluations are done though on line mode. A new trend in implementing virtual trainer in Muti-user Virutal Reality system is discussed in this paper. The awareness of computer-based training is analyzed with employees of different categories. This method also leads to the development of effective implementation of web based virtual trainer through out the world in the near future.
be a perfect choice. It is well known by women, easy to use, anatomically perfect, and it has the size to accommodate all the above-mentioned features. The tampon like the shape presented in Figure 10 has a conceptual designof the new proposed sensor. As may be seen, the thermistor is placed on the top of the container, the electronic circuit in the body of the container, and the battery on the tail. The enclosure to fulfill all the health conditions needs to be properly closed and avoid any way of contact with the exterior part. As known, the vagina is a humid place and no fluid should make contact with the electronic part to avoid electric conductivity. The electric current range used to power this circuit is not too high but enough to cause some health damages in sensitive and tender skin like burns or others injuries.