Single-Feed Dual-Band Circularly Polarised Microstrip Antenna

A novel technique for obtaining dual-hand circular polarization (CP) radiation of a single-feed circular microstrip antenna in proposed and demonstrated. By embedding two pain of arc shaped slots of proper lengths close to the boundary of a circular patch, and protruding one of the arc-shaped slots with a narrow slit, the circular microstrip antenna can perform dual-hand CP radiation using a single probe feed. Details of the antenna design

A Strip-Loaded Feed-Horn Antenna

Design and development of a new feed -horn antenna with low sidelobe levels is reported . The E-walls of this antenna are fabricated with low -loss dielectric substrate , periodicallyloaded with thin conducting strips . The antenna is found to be simulating the radiation characteristics of metallic Corrugated horns . This can be an ideal substitute for metallic Corrugated horns with added advantages like light -weight and low production cost

Single-feed dual-frequency dual-polarized slotted square microstrip antenna

A novel dual frequency dual-polarized square microstrip patch antenna embedded with a slot is presented. The proposed antenna offers tunability of the frequency ratio between the two frequencies by adjusting the slot dimensions. This configuration also provides a size reduction up to -51 and 35% for the two modes as compared to a square micro strip patch antenna

Wide Band Rectangular Microstrip Antenna using Symmetric T-shaped Feed

Bandwidth enhancement of a rectangular microstrip antenna using a T-shaped microstrip feed is explored in this paper. A 2:1 VSWR impedance bandwidth of 23% is achieved by employing this technique. The far-field patterns are stable across the pass band. The proposed antenna can be used conveniently in broadband communications

A Wideband Rectangular Microstrip Antenna Using an Asymmetric t-shaped Feed

An electromagnetically coupled T-shaped microstrip feed used to enhance the impedance bandwidth of a rectangular microstrip antenna is reported. The proposed antenna offers a 2:1 VSWR bandwidth of -36% with an increase in gain of 0.8 dB

Wideband Oylindrioal Dielectric Resonator Antenna Excited Using an L-strip Feed

A broadband cylindrical dielectric resonator antenna (DRA) energized with an L-strip feed is presented The novel exciting technique achieves a 2:1 VSWR bandwidth of 18%. The variation of bandwidth for different feed parameters is also studied

Wideband Microstrip Antenna Using Hook-Shaped Feed

In this paper, we introduce a novel feeding technique for bandwidth enhancement of a rectangular microstrip antenna This antenna offers an impedance bandwidth of 22% without degrading the effciencv. The effect of the feed parameters upon patch characteristics such as resonant frequency, impedance bandwidth, and radiation pattern are studied in detail. The experimental results are verified using the FDTD results

Corrugated Flanged Horn Feed for Offset Paraboloidal Reflectors

A technique for improving the coupling between a feed horn and reflector by using corrugated metallic flanges is presented. Experimental data for flanges of varying parameters are given and theoretical explanation is supplemented

A Circularly Polarized Corrugated Flanged Feed Horn

Design and development of a circularly polarized and matched H-plane sectorial horn antenna have been reported By proper trimming of the flange parameters any desired polarization can be obtained from the horn

A Strip-Loaded Feed-Horn antenna

Design and development of a new feed -horn antenna with low sidelobe levels is reported . The E-walls of this antenna are fabricated with low -loss dielectric substrate , periodically loaded with thin conducting strips . The antenna is found to be simulating the radiation characteristics of metallic corrugated horns . This can be an ideal substitute for metallic corrugated horns with added advantages like light -weight and low production cost.

A Strip-Loaded Feed-Horn antenna

Design and development of a new feed -horn antenna with low sidelobe levels is reported . The E-walls of this antenna are fabricated with low -loss dielectric substrate , periodically loaded with thin conducting strips . The antenna is found to be simulating the radiation characteristics of metallic corrugated horns . This can be an ideal substitute for metallic corrugated horns with added advantages like light -weight and low production cost.

Development of a new type of simulated scalar feed

This thesis presents the results of an investigation conducted for the development of a new type of feed horn antenna called "Simulated Scalar Feed". A schematic presentation of the work is given below. A review of the past important work done in the field of conventional/multimode electromagnetic horn antennas is presented in the first part of the second chapter. The work carried out on corrugated horns and surfaces are included in the second part of the review. In the third part, work on dielectric and dielectric loaded metal horns are reviewed. In all the parts of the review, special emphasis is given to theoretical design considerations. The methodology adopted for the experimental investigations is presented in the third chapter. The instrumentation utilized and thThis thesis presents the results of an investigation conducted for the development of a new type of feed horn antenna called "Simulated Scalar Feed". A schematic presentation of the work is given below. A review of the past important work done in the field of conventional/multimode electromagnetic horn antennas is presented in the first part of the second chapter. The work carried out on corrugated horns and surfaces are included in the second part of the review. In the third part, work on dielectric and dielectric loaded metal horns are reviewed. In all the parts of the review, special emphasis is given to theoretical design considerations. The methodology adopted for the experimental investigations is presented in the third chapter. The instrumentation utilized and the details of fabrication ofe details of fabrication of the new simulated scalar feed are described. The method of measurements of radiation characteristics of the antenna are also explained in this chapter. In the fourth chapter the outcome of the experimental results of the investigations carried out on horn antennas fabricated with different physical dimensions and different parameters for the E—plane boundary walls are highlighted. The theoretical explanation used to explain the experimental results is given in the fifth chapter of the thesis. A comparison between the experimental and the theoretical results is also presented in this chapter. In chapter six, the conclusions drawn from the experimental as well as the theoretical investigations are discussed. The advantages and features of the newly developed simulated scalar feed is examined in this chapter. Scope of further investigations in this field is also discussed at the end of this chapter.

Efficacy of fermented prawn shell waste as a feed ingredient for Indian white prawn, Fenneropenaeus indicus

Prawn shell waste collected from shrimp-processing plants in Cochin, India, was subjected to fermentation using 20 chitinoclastic and proteolytic/non-proteolytic bacterial strains. The products generated were analysed for protein, lipid, total sugars, N-acetyl glucosamine, free amino acids and ash. Shrimp diets were prepared using these 20 fermented products and a control diet using raw prawn shell waste. Feeding experiment was conducted with postlarvae (PL21) of Indian white prawn, Fenneropenaeus indicus for a period of 21 days. Biogrowth parameters such as mean weight gain, feed conversion ratio, specific growth rate and protein efficiency ratio were estimated and the animals were challenged with white spot virus orally via diet. Enhanced growth could be observed in prawns fed F134 and F124, incorporated with the fermentation products generated using Bacillus spp., C134 and C124 respectively. The percentage survival of prawns after 7 days of challenge was found to be highest for groups fed diet F111 incorporated with fermentation product generated using Bacillus sp. These products of bacterial fermentation hold promise as growth enhancers and immunostimulants in aquaculture. KEY WORDS: biogrowth parameters, feed

A Novel Planar Fractal Antenna with CPW-Feed for Multiband Applications

In this paper, a multiband antenna using a novel fractal design is presented. The antenna structure is formed by inscribing a hexagonal slot within a circle. This base structure is then scaled and arranged within the hexagon along its sides without touching the outer structure. The proposed CPW fed, low profile antenna offers good performance in the 1.65 – 2.59 GHz, 4.16 – 4.52 GHz and 5.54 – 6.42 GHz bands and is suitable for GSM 1800/1900, Bluetooth, IMT advanced systems and upper WLAN applications. The antenna has been fabricated on a substrate of height 1.6 mm and εr = 4.4 and simulation and experimental results are found to be in good agreement

A Triple-Mode Feed-Forward Sigma-Delta Modulator Design For Gsm / Wcdma / Wlan Applications

This paper presents a cascaded 2-2-2 reconfigurable sigma-delta modulator that can handle GSM, WCDMA and WLAN standards. The modulator makes use of a low-distortion swing suppression topology which is highly suitable for wide band applications. In GSM mode, only the first stage (2nd order Σ-Δ ADC) is turned on to achieve 88dB dynamic range with oversampling ratio of 160 for a bandwidth of 200KHz; in WCDMA mode a 2-2 cascaded structure (4th order) is turned on with 1-bit in the first stage and 2-bit in the second stage to achieve 74 dB dynamic range with oversampling ratio of 16 for a bandwidth of 2MHz and a 2-2-2 cascaded MASH architecture with a 4-bit in the last stage to achieve a dynamic range of 58dB for a bandwidth of 20MHz. The novelty lies in the fact that unused blocks of second and third stages can be switched off taking into considerations like power consumption. The modulator is designed in TSMC 0.18um CMOS technology and operates at 1.8 supply voltage.