Investigations On A Microstrip Excited Rectangular Dielectric Resonator Antenna

The thesis relates to the investigations carried out on Rectangular Dielectric Resonator Antenna configurations suitable for Mobile Communication applications. The main objectives of the research are to: - numerically compute the radiation characteristics of a Rectangular DRA - identify the resonant modes - validate the numerically predicted data through simulation and experiment 0 ascertain the influence of the geometrical and material parameters upon the radiation behaviour of the antenna ° develop compact Rectangular DRA configurations suitable for Mobile Communication applications Although approximate methods exist to compute the resonant frequency of Rectangular DRA’s, no rigorous analysis techniques have been developed so far to evaluate the resonant modes. In this thesis a 3D-FDTD (Finite Difference Time Domain) Modeller is developed using MATLAB® for the numerical computation of the radiation characteristics of the Rectangular DRA. The F DTD method is a powerful yet simple algorithm that involves the discretimtion and solution of the derivative form of Maxwell’s curl equations in the time domain.

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

Design of a Compact Multiband Microstrip Antenna

A compact microstrip multiband antenna on a modified ground plane which can operate over the bands starting from 900 MHz to 5.35 GHz which includes the GSM (880-960) GPS (1568-1592 MHz), DCS (1710-1880 MHz), and PCS (1850- 1990 MHz). UMTS (1920-2170 MHz), IEEE 802.11 b/g (2400- 2484) and WLAN IEEE 802.11a band (5.15-5.35) is reported in this paper. The overall dimension of the antenna is 33 x 33 mm2 including the top patch with a dimension 22 x 22 mm2. The experimental results of the antenna are presented in this paper. The results confirm that the antenna exhibits wide band characteristics and covers 7 bands of operation

Compact Coplanar Waveguide Fed Ground Meandered Antenna for Wireless Application

A compact Co-Planar Waveguide (CPW) fed antenna operating at 2.4GHz with 300MHz 2:1 VSWR bandwidth is presented. Compared to a conventional quarter wavelength CPW fed monopole antenna, the aperture area reduction of the present antenna is 85%. The prototype antenna fabricated on a substrate of εr = 4.4 and thickness 1.6mm is only 22x10x1.6mm3. This much size reduction and impedance matching is achieved by adjusting the signal to ground plane separation and meandering the ground plane of a 50Ω CPW transmission line

Rectangular Dielectric Resonator Antenna Configurations For Mobile Communication Applications

Experimental investigations on Microstrip line excited Dielectric Resonator Antenna configurations suitable for Mobile Communication applications are reported. High permittivity (εrd = 48) resonator samples with different aspect ratios are employed for the study. Theoretical analysis performed using FDTD method is also presented.

Octagon Shaped Microstrip Patch Antenna For Dual Band Applications

The paper proposes an octagon shaped Microstrip Patch Antenna suitable for dual band applications. The striking features of this compact, planar antenna are sufficient isolation between the two operating bands and an area reduction of - 29% in comparison to a conventional circular patch antenna operating in the same band

A Compact Modified Ground CPW Fed Antenna for UWB Applications

A Coplanar waveguide fed compact planar monopole antenna with a modified ground plane is presented. Measured and simulated results reveal that the antenna operates in the Ultra Wide Band with almost constant group delay throughout the band. Developed design equations of the antenna are validated for different substrates. Time domain performance of the antenna is also discussed in order to assess its suitability for impulse radio applications

Electromagnetically Coupled Dual Port, Dual Band, Octagonal Patch Antenna

In this paper, a dual port, dual frequency, dual polarized, octagonal shaped Microstrip patch antenna, suitable for GPS applications is discussed experimentally and theoretically. The proposed antenna configuration is characterized by good impedance bandwidth, gain, isolation between two ports and broad radiation patterns

Octagonal Microstrip Patch Antenna For Dual Band Applications

A dual port dual polarized octagonal microstrip patch antenna suitable for dual band applications is discussed theoretically and experimentally. The antenna exhibits good impedance bandwidth, gain and broad radiation patterns. Parameters predicted by the Conformal Finite Difference Time Domain algorithm show good agreement with the simulated results and experimental observations

Compact CPW-fed uniplanar antenna for multiband wireless applications

A compact coplanar waveguide (CPW) fed uniplanar antenna for Quad-band applications is presented. The Quad-band operation is realized by imposing various current paths in a modified T-shaped radiating element. The antenna covers GSM 900, DCS 1800, IEEE802.11.a, IEEE802.11.b and HiperLAN-2 bands and exhibits good radiation characteristics. This low profile antenna has a dimension of 32mm×31mmwhen printed on a substrate of dielectric constant 4.4 and height 1.6mm. Details of design with experimental and simulated results are presented

CPW-Fed Quad-Band Antenna for Compact Wireless Application

This paper presents the design and development of a compact CPW fed quad band antenna. This low profile antenna has a dimension of 32mmx31mm when printed on a substrate of dielectric constant 4.4 and height 1.6mm. The antenna covers GSM 900, DCS 1800, IEEE802.11.a, IEEE802.11.b and HiperLAN2 bands. The antenna exhibits good radiation characteristics with moderate gain

Design of a Compact Genetic Microstrip Antenna with improved performance

In this paper the design issues of compact genetic microstrip antennas for mobile applications has been investigated. The antennas designed using Genetic Algorithms (GA) have an arbitrary shape and occupies less area (compact) compared to the traditionally designed antenna for the same frequency but with poor performance. An attempt has been made to improve the performance of the genetic microstrip antenna by optimizing the ground plane (GP) to have a fish bone like structure. The genetic antenna with the GP optimized is even better compared to the traditional and the genetic antenna.

Comments on Simple and Accurate Formula for the Resonant Frequency of the Equilateral Triangular Microstrip Patch Antenna

Antennas and Propagation, IEEE Transactions on,VOL 48,issue 4,pp 636

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.

Theoretical investigations of an annular elliptical ring microstrip antenna using Green‘s function technique

Analytical expressions for the Green’s function of an annular elliptical ring microstrip antenna (AERMA) are developed and reported. The modal, radiation and input impedance characteristics of the TM, modes are determined from these expressions. The resonant frequencies of odd modes are greater than that of the even modes for all TMnl modes (n = 1, 2, 3, ...) udke elliptical microstrip structures. The radiation pattern and input imedance curves of TMI2 mode on comparison with available experimental result shows good agreement whch provides an independent validation to this technique. The performance of the AERMA is then investigated as a function of thickness and substrate dielectric permittivity.