Vibha Rani Gupta

Microwave Dielectric Properties of Ni 0.2 Cu X Zn 0.8-X FE 2 O 4 for Application in Antenna

Structural, vibrational and microwave dielectric properties of Nickel-Copper-Zinc ferrite (Ni0.2CuxZn0.8−xFe2O4) ceramics have been presented in this paper. Samples have been prepared using conventional auto-combustion method. The X-ray diffraction (XRD) results confirmed the ferrite samples to be of cubic spinel structure, which further was validated by Fourier transform infrared (FT-IR) and Raman spectroscopy. The relative permittivity (εr) increased from 7.474 to 8.132 with successive increase in Cu content. The observed and calculated permittivity using ClausiusMossoitti relation have been in good agreement. The temperature coefficient of resonant frequency (τf ) decreased from −75.85 ppm/◦C to −32.12 ppm/◦C with increase in successive Cu content. The relative permeability (μr) have been calculated by using the Nicholson-Ross-Weir conversion technique. Using Ni0.2Cu0.2Zn0.6Fe2O4 sample the ferrite resonator antennas have been designed in three different shapes. The experimental and theoretical characteristics of the antennas have been compared and a good agreement has been achieved.

Reduced size, dual frequency band antenna for wireless communication

In the present paper a novel compact, probe fed microstrip patch antenna for operation in dual frequency mode is proposed. The novel design is achieved by cutting grooves in the four edges of the microstrip antenna and etching out a symmetrical pattern of V grooves. Reduction in patch area of about 39 % with respect to the traditional circularly polarized square patch, operating at the same frequency is obtained. Moreover, the 50 ohms feed position is optimized by moving the feed point along one of the axes of the patch, leading to ease in fabrication.

Neural network model for designing monopole antenna

In this paper, a neural network model is proposed which can be used for designing any monopole antenna whose element is square shaped and required to exhibit a wide band characteristics. All the antennas designed using this model shows a wideband response between 4.5 GHz - 5 GHz. This model is prepared using Feed Forward Back Propagation Algorithm. The results given by the prepared model are compared with the results of IE3D software which shows a very good agreement. Therefore, this model is accurate enough to yield the parameters of the monopole antenna thus eliminating the long time consuming process of determining various design parameters using costly software packages.

Microstrip loop antenna for wearable applications

This paper presents a microstrip rectangular loop antenna for wearable application. The substrate used for the prototype model is a FR4 material. The designed antenna can be integrated with a watch and is suitable for the wearable application. The characteristics of the prototype antenna developed, are measured in terms of the return loss, VSWR bandwidth, and radiation pattern. It is found that the fabricated antennas possess 210 MHz VSWR Bandwidth. This antenna can be placed over the outer ring a rectangular watch without disturbing the wearing comfort.

Far end crosstalk reduction in two nearby transmission lines

In this paper, we have proposed a method to reduce the crosstalk between two nearby transmission lines. This is achieved by inserting rectangular slots in the steps of the stepped transmission line, which helps to reduce the coupling between the two lines. To this end, parametric studies have been carried out to get an intuition regarding the underlying processes conducted to the far end crosstalk, thereby enabling to optimize the far end crosstalk. The conventional transmission line is used as a benchmark and then the proposed structure is compared with it. The coupled circuit model is studied in terms of S-parameters namely, S11 and S21, S31 and S41. The result shows that the far end crosstalk is reduced by almost 6 dB over the entire range of UWB application.

Slotted planar microstrip antenna for HIPERLAN/2 application

In the present work, a multi-slot loaded proximity coupled microstrip antenna for HIPERLAN/2 applications is proposed. The patch comprises of a U-shaped slot and two rectangular slots. The proposed antenna has been simulated on IE3D Software. Results show that the antenna has a bandwidth of 4.3% and gain is more than 3dBi over the entire range of operating frequency. The major advantage of this antenna is that it covers the entire frequency spectrum used for HIPERLAN/2.

Implantable Antenna for Blood Glucose Monitoring

In this paper, a miniaturized implantable antenna for ISM (industrial, scientific and medical) band 2.4–2.4835 GHz has been proposed. The designed antenna can be used for biomedical application called blood glucose monitoring system. The proposed antenna will be placed under the skin tissue. To make the antenna biocompatible, it is coated with the PMMA (polymethylmethacrylate) biocompatible layer. The designed antenna is tested for single-layer skin tissue as well as multilayer muscle and skin tissue.

Compact magneto-dielectric resonator MIMO antenna for angle diversity

This paper presents a two-element MIMO antenna configuration designed using magneto-dielectric (MD) material. The MD material has been designed such that its temperature coefficient value approaches zero. The microwave dielectric constant and permeability of the material is calculated by Nicholson-Ross-Weir conversion technique and found to be 8.02 and 1.64, respectively. Each element is designed so that it can operate at 5.71 GHz. The two elements of the MIMO configuration are separated by quarter wavelength and half wavelength and are compared. The designed antenna can give a quad-directional radiation property, which can be utilized for the diversity scheme.

Butler Matrix Fed Exponentially Tapered H-Plane Horn Antenna Array System Using Substrate Integrated Folded Waveguide Technology

This paper introduces the implementation of 4 × 4 Butler matrix fed antenna array system using substrate integrated folded waveguide (SIFW) technology. The antenna array system generates four directive beams in different angular directions with gain and half power beam width (HPBW) of 6.43, 6.43, 6.33, and 6.43 dB and 12o, 9o, 10o, and 10o. These directive beams will help to suppress the interfering signals from unwanted users, and hence, the quality of high-speed wireless communication will be improved.

Improvement of Radiation Performances of Butler Matrix-Fed Antenna Array System Using 4 × 1 Planar Circular EBG Units

Excitation of surface waves in the microstrip patch antenna at higher frequencies degrades the overall radiation performances. To overcome this problem, electromagnetic band gap (EBG) structures can be used. In this paper, the improvement of radiation performances of a Butler matrix-fed antenna array system has been obtained by incorporating 4 × 1 planar circular EBG units in the form of metallic patches between the array elements as well as beneath the radiating patches as circular slots. Finally, symmetric gain has been obtained for all the radiated beams at 14.5 GHz.