Nipun K. Mishra

Bandwidth Enhancement of Cylindrical Dielectric Resonator Antenna Using Thin Dielectric Layer Fed by Resonating Slot

Abstract In this paper Cylindrical Dielectric Resonator Antenna (CDRA) has been designed for X-band frequency range applications with slot feeding. Bandwidth of designed cylindrical dielectric resonator antenna has been enhanced by making the slot to be resonating and inserting very thin low permittivity dielectric layer between the slot and CDRA. Resonating slot excites the closely spaced HEM11δ and HEM21δ mode inside the antenna as well as provides the resonance at the upper side of desired X-band. Low profile low permittivity layer provides the excellent matching of these modes and shift the HEM21δ mode to higher frequency side at 11.25 GHz with better impedance matching. By combining all of three resonances, nearly 85 % increment in impedance Bandwidth has been obtained with reference to non resonating slot excited CDRA. Fractional impedance bandwidth for proposed design is 48 % and average Gain of 6 dB with more than 92 % radiation efficiency has been shown by the antenna throughout the desired band with broadside pattern.

Investigation of Binomial and Chebyshev Distribution on Dielectric Resonator Antenna Array

For wireless communication systems, the antenna is one of the most critical components for transmission as well as reception point of view. Good design of the antenna can relax system requirements and improve overall system performance. In addition to receiving or transmitting energy, an antenna in an advanced wireless system is usually required to optimize or accentuate the radiation energy in some directions and suppress it in others. Thus the antenna must also serve as a directional device in addition to a probing device. Many applications require radiation characteristics that may not be achievable by a single element. It may, however, be possible that an aggregate of radiating elements in an electrical and geometrical arrangement (an array) will result in the desired radiation characteristics [1]. The arrangement of the array may be such that the radiation from the elements adds up to give a radiation maximum in a particular direction or directions, minimum in others, or otherwise as desired. In this paper we concentrated on the electrical and geometrical properties of array elements that give a radiation maximum in a particular direction and minimum in others. We investigate the binomial and chebyshev distribution for linear and rectangular dielectric resonator antenna array.

Performance analysis of micro-strip patch antenna and Dielectric Resonator Antenna array

A substantial progress has been made in the wireless technology at a formidable rate during the past decade, thereby creating new and improved services at lower costs, which has accounted in increased in air time usages and number of subscribers. Due to explosive growth of wireless services and rapidly increasing number of users, the need for wider coverage area and higher transmission quality are also growing very fast. For this, a more efficient use of the radio spectrum is required. Once the spectrum for a system has been allotted and implemented, then it is very tedious and challenging task to provide services to new added subscribers. The most practical solution to these problems is to exploit spatial processing or smart antenna systems [1]. This can be achieved by use of antenna arrays, and the number of beams in a sector (e.g., 120°) which is a function of the array geometry. In this paper we investigated the performance of Micro-strip patch and Dielectric Resonator Antenna (DRA) for different array geometry. We compared both antennas in terms of substrate material, dimension & feeding position and tried to optimize the antenna performance for linear and rectangular array. We also tried to find out the factor behind the changing the directivity and its radiation efficiency of an antenna.

Effect of homoeopathic treatment on filariasis: A single blind 69-months follow-up study in an endemic village in Orissa

Abstract A single blind follow-up study was undertaken to assess the effect of homeopathic treatment on microfilarial clearance and frequency of filarial fevers in an endemic village, India, State of Orissa. Homoeopathic treatment effectively reduced the frequency of filarial fevers by 20 per cent (P

Circularly Polarized Cylindrical Dielectric Resonator Antenna coupled by V-shaped resonating slot

In this paper circularly Polarized Dielectric Resonator Antenna for the Satellite frequency applications has been designed. With proper design the proposed Cylindrical DRA fed by centered V-shaped slot; is showing characteristics of Circular Polarization in the desired band. Two orthogonal arms of symmetrically centered V-shaped slot having same dimension excite the TM01δ modes at 9.75GHz as well as slots itself are resonating at 8.5 GHz. Crossing of λ/4 long micro strip line between both slots at an angle of 45° is generating the nature of circular polarization near the 8GHz frequency range. Axial Ratio bandwidth (AR ≤ 3 dB) of 9% (720MHz) and impedance bandwidth (S11 ≤ −10 dB) of 28% (2.47GHz) has been shown by the antenna which can be considered large axial ratio bandwidth for single and simple feed CDRA. Proposed antenna has shown average gain of more than 6 dBi in broadside direction with more than 95% radiation efficiency in desired band.