Modified Circular Patch Antenna

A circular miqrostrip antenna with a modified structure is presented. By adjusting the feed location along the circumference of the patch it is possible to match the antenna with a C microstrip line of any impedance. The impedance bandwidth and radiation characteristics are unaffected by this structural V modification.

Mechanical Properties of Short-Isora-Fiber-Reinforced Natural Rubber Composites: Effects of Fiber Length, Orientation, and Loading; Alkali Treatment;and Bonding Agent

A series of short-isora-fiber-reinforced natural rubber composites were prepared by the incorporation of fibers of different lengths (6, 10, and 14 mm) at 15 phr loading and at different concentrations (10, 20, 30, and 40 phr) with a 10 mm fiber length. Mixes were also prepared with 10 mm long fibers treated with a 5% NaOH solution. The vulcanization parameters, processability, and stress-strain properties of these composites were analyzed. Properties such as tensile strength, tear strength, and tensile modulus were found to be at maximum for composites containing longitudinally oriented fibers 10 mm in length. Mixes containing fiber loadings of 30 phr with bonding agent (resorcinol-formaldehyde [RF] resin) showed mechanical properties superior to all other composites. Scanning electron microscopy (SEM) studies were carried out to investigate the fiber surface morphology, fiber pullout, and fiber-rubber interface. SEM studies showed that the bonding between the fiber and rubber was improved with treated fibers and with the use of bonding agent.

Polarisation agile active microstrip patch arrays

Two three-clement polarisation-agile active microstrip patch arrays have been developed . The radiating elements are square patches each with two transistors mounted on adjacent edges. The patches radiate orthogonal modes , the relative phase of which can be varied. Radiation patterns show good agreement with predictions from theory, in both linear and circular polarization, and no grating lobes were observed

A new broadband circular patch antenna

A simple technique to improve the impedance bandwidth of a circular microstrip patch antenna using two sectorial slots is proposed. Using this design more than 5% impedance bandwidth is obtained. The added advantage of this new antenna is that it can be fed by a 50- microstrip line

A novel H-shaped patch antenna

A novel H-shaped patch antenna suitable for wireless and satellite communications is presented. The new antenna has some advantages compared to conventional microstrip patch antennas, such as small size, a fewer number of modes, no harmonic resonance, and the provision of pure reactive impedances at its harmonics that can result in increasing the transmitter efficiency. The basic principles and design procedure are introduced. Two antennas at two different frequencies, 4 and 10 GHz, are designed, fabricated, and measured. The measured results show a good agreement with the predicted ones

A Microstrip Patch Resonator with a Via Connecting Ground Plane

patch resonator with a via connecting ground plane is proposed and studied experimentally. The resonant frequency of this patch resonator is tunable up to about 34 % by adjusting the via position in the center line. The lowest resonant frequency of this patch resonator has been reduced by more than 64% of the same size patch resonator

A new microstrip patch antenna for mobile communications and bluetooth applications

compact multihand planar octagonal-shaped microstrip antenna simultaneously suitable for mobile communication and blue tooth application is presented. The antenna provides sufficient isolation benveen the two operating bands and an area reduction of -29 % with respect to a circular patch operating in the same band

Enhanced Bandwidth Microstrip Patch Antennas Loaded with High Permittivity Dielectric Resonators

A novel technique fitr the bat dividth enhancement of conventional rectangular microstrip antenna is proposed in this paper. When a high permittivity dielectric resonator of suitable resonant frequency was loaded over the patch. the % bandwidth of the antenna was increased by more than five tunes without much affecting its gain and radiation performance. A much more improved bandwidth was obtained when the dielectric resonator was placed on the feedline. Experimental study shows a 2:1 VSWR bandwidth of more than 10% and excellent cross polarization performance with increased pass band and radiation coverage abnost the same as that of rectangular microstrip antenna

A Broadband Slope-Strip-Fed Micro strip Patch Antenna

A novel slope -strip feeding technique for a microstrip antenna is presented in order to achieve a broad bandwidth. The experimental results show that the optimal bandwidth attained is 53.4% for less than -10-dB return loss

A New Broadband Circular Patch Antenna

A simple technique to improve the impedance bandwidth of a circular microstrip patch antenna using two sectorial slots is proposed. Using this design more than 5% impedance bandwidth is obtained. The added advantage of this new antenna is that it can be fed by a 50 microstrip line.

INVESTIGATIONS ON SLOT-LOADED SQUARE MICROSTRIP PATCH ANTENNAS FOR COMPACT DUAL FREQUENCY DUAL POLARIZED OPERATIONS

The thesis is the outcome of the experimental and theoretical investigations carried out on a novel slotted microstrip antenna.The antenna excites two resonance frequencies and provides orthogonal polarization. The radiation characteristics of the antenna are studied in detail. The antenna design is optimized using IE3D electromagnetic simulation tool. The frequency-Difference Time-Domain (FDTD) method is employed for the analysis of the antenna.The antenna can be used for personal and satellite communication applications.

Market Orientation in Indian Seafood Processing Firms

This thesis studied the impact of market orietnation on business performance, in the seafood industry, which is a unique situation wherein the firms were all 100% export oriented. The study was able to prove that in the context of the seafood indsutry, implementation of market orientation principles will lead to increase in business performance. The business performance variables were measured under two heads, namely economic performance and non-economic performance. Market orientation in Indian seafood firms was significantly and postiively related to both the performance measures. Under the non-economic performance, were the customer and employee consequences.Again market orientation was positively and significantly related to both the consequences.Thus, the implication arising from the study is this: market orientation in Indian seafood processing firms increases their business performance. The implementation of market orientation will help the seafood firms in gaining competitve advantages in exporting. This in turn will result in increased exports and the position of Indian seafood in the global market will be strengthened. It will thus become a leading player in the global fish trade. Next, the focus was on the effect of the antecedents on the market orientation of a firm. It was seen that several factors were antecedents to the adoption of market orientation principles. They include top management emphasis, conflict, centralization and reward system. It is noted that top management emphasis and support is vital to the market orientation programme. The top management needs to adopt market oriented behaviour and reinforce the need for being market oriented, for it to percolate down the line.Interdepartmental conflict is seen to affect market orientation positively. A large percent of the Indian seafood firms are traditionally family-owned companies, rather than professionally managed firms. This would result in promulgation of old ideas of management whereby, conflict was seen as a healthy exercise, which helped to build up each department's efficiency. But, this view in the long run proves to be detrimental to the firm's performance and must therefore be kept to a bare minimum, if any.Decentralisation of decision making facilitates the participation of the lower level employees and builds up their motivational levels and commitment to the firm. Thus employees are encouraged to make their own decisions, so that they can deal with customers faster and more efficiently. Reward systems help improve an employee's morale, provide encouragement and helps inculcate commitment and loyalty. It improves the employee's self worth and fulfills his need for achievement. A satisfied employee works better, produces more output and needs less supervision, and is happy, thereby reducing costs to the company for replacement and retraining, if the employee quits.Competitive intensity plays a moderating role on the market orientation business performance. Thus in times of greater competition, the relationship between market orientation and business performance grows stronger. Thus, this thesis was successful in investigating a positive relationship between business performance and market orientation.

Design and Development of re configurable compact cross patch antenna for switchable polarization

Antennas are necessary and vital components of communication and radar systems, but sometimes their inability to adjust to new operating scenarios can limit system performance. Reconfigurable antennas can adjust with changing system requirements or environmental conditions and provide additional levels of functionality that may result in wider instantaneous frequency bandwidths, more extensive scan volumes, and radiation patterns with more desirable side lobe distributions. Their agility and diversity created new horizons for different types of applications especially in cognitive radio, Multiple Input Multiple Output Systems, satellites and many other applications. Reconfigurable antennas satisfy the requirements for increased functionality, such as direction finding, beam steering, radar, control and command, within a confined volume. The intelligence associated with the reconfigurable antennas revolved around switching mechanisms utilized. In the present work, we have investigated frequency reconfigurable polarization diversity antennas using two methods: 1. By using low-loss, high-isolation switches such as PIN diode, the antenna can be structurally reconfigured to maintain the elements near their resonant dimensions for different frequency bands and/or polarization. 2. Secondly, the incorporation of variable capacitors or varactors, to overcome many problems faced in using switches and their biasing. The performances of these designs have been studied using standard simulation tools used in industry/academia and they have been experimentally verified. Antenna design guidelines are also deduced by accounting the resonances. One of the major contributions of the thesis lies in the analysis of the designed antennas using FDTD based numerical computation to validate their performance.

Investigations on the Radiation Characteristics of Broadband Strip Loaded Slotted Microstrip Antennas

With the recent progress and rapid increase in mobile terminals, the design of antennas for small mobile terminals is acquiring great importance. In view of this situation, several design concepts are already been addressed by the scientists and engineers. Compactness and efficiency are the major criteria for mobile terminal antennas. The challenging task of the microwave scientists and engineers is to device compact printed radiating systems having broadband behavior, together with good efficiency. Printed antenna technology has received popularity among antenna scientists after the introduction of microstrip antenna in 1970s. The successors in this kind such as printed monopoles and planar inverted F are also equally important. Scientists and Engineers are trying to explore this technology as a viable coast effective solution for forthcoming microwave revolution. The transmission line perspectives of antennas are very interesting. The concept behind any electromagnetic radiator is simple. Any electromagnetic system with a discontinuity is radiating electromagnetic energy. The size, shape and the orientation of the discontinuities controls the radiation characteristics of the system such as radiation pattern, gain, polarization etc. It can be either resonant or non resonant structure. Microstrip antennas are suitable for wireless applications due to their low cost, high gain and ease of fabrication. But the major disadvantage of micro strip antennas is their inherent narrow bandwidth. A lot of techniques are introduced by the researchers all over the world to enhance the bandwidth of micro strip patch antennas. The thesis addresses an attempt to enhance the bandwidth of micro strip patch antennas by incorporating impedance matching strip as a part of the micro strip patch antenna. The first part of the thesis deals with the broadband operation of the tilted square slot and polygonal slot loaded square micro strip patch antennas. The resonant mechanisms are clearly mentioned using the simulation and experimental studies. The bandwidth of the polygonal slotted broadband patch antenna is again enhanced by implementing an Lstrip feed mechanism. In the second major part of the thesis, a novel gain enhancement technique for single band and broadband square micro strip patch antennas is achieved by implementing offset stacked configurations.

Marketing orientation of small Firms- a study with reference to Trivandrum district

The small business has attracted very little attention of the historians in the ancient times, or public mind inspite of the fact that its impact on the various civilisations has been phenominal. Even in recent times economists considered the small firms as inappropriate, obselate and anacronistic as it cannot assimilate the full potential of technological change in the production system. But today everybody agrees that the small business has a definite role in shaping the human destiny and enhancing the quality of life in any society. In a developing country like India small firms are necessary to generate employment for millions, high standared of personal choice to consumers, provide competition and act as a check to monopoly power; further the small firms provide an important source of innovation and in turn it paves the way for entrepreneur development in the society. In many countries the small enterprises played a significant role in the growth and development of their economic system. Italy and Japan are quoted as classic examples . In India, too, with the abundance of labour and scarce capital resources small firms have been promoted and protected by the government. But one must say that the small firm owners/managers in India have been shy in developing a market orientation in themeselves. Due to this many firms failed and closed. The alarming rate of sickness among the small firms in India may be attributed to the lack of market driven/customer orientation approach among the owner/managers of small business. So the study on the market oreintation of the small firms has never been in the mind of marketing experts and academicians. Thus, an attempt is made to enquire into them systematically and scientifically. For the study, Trivandrum district in Kerala has been selected. The data for the study has been collected by the help of a schedule which has been prepared after consulting the relevant literature and after consultation with experts in the field, academicians and practising managers.